Answer: Option A
Explanation:
The drug AZT belongs to the group of drugs that is used in case of HIV. These class of drugs are known as Nucleoside analogues.
This drug interferes with the enzyme reverse trsncriptase which is used by the cells affected from HIV for the production of new viruses.
So, this drug reduces the activity of reverse transcriptase which reduces the chances of the cells to divide further to new HIV infected cell.
Hence, the correct answer is option A
Which of the following statements is TRUE of restriction enzymes?
(A)they are not naturally produced by bacteria, but are bioengineered by humans.
(B)they cleave DNA only at sites of adjacent thymine bases.
(C)there are less than 10 restriction enzymes known.
(D)they cut at random sites within a genome. they protect bacterial cells from invasion by foreign DNA.
Final answer:
The true statement about restriction enzymes is that they protect bacterial cells from foreign DNA invasions by specifically recognizing and cutting at particular DNA sequences known as restriction sites.
Explanation:
Which of the following statements is TRUE of restriction enzymes? The correct answer is that restriction enzymes protect bacterial cells from invasion by foreign DNA. Restriction enzymes (also called restriction endonucleases) are naturally produced by bacteria and act as a defense mechanism against foreign DNA, such as those introduced by bacteriophages. Each restriction enzyme recognizes a specific DNA sequence, usually consisting of four to six nucleotides, and catalyzes double-strand breaks at or near this recognition site (also known as a restriction site). Far from being limited in number, over 3000 different restriction enzymes have been identified, and they do not cut DNA at random sites nor solely at sites of adjacent thymine bases.
How do hormones influence the onset of puberty?
Answer:
At a certain age, the hypothalamus which is an essential part of the brain that releases a gonadotrophin-releasing hormone which stimulates the pituitary to release two important hormones luteinizing hormone and follicle-stimulating hormone.
These hormones transported through the blood to the testicle and ovary in boys and girls respectively. In boys, LH and FSH reach the testicle and start production of another hormone testosterone which helps in the development procedure and changes in the body.
In girls, the LH and FSH stimulate the ovary and start producing estrogen which helps in puberty which is changes in the body and prepares the body for pregnancy.
Thus, these hormones are responsible for the onset of puberty.
A specific molecule was separated from a yeast cell and then placed in a flask to find out if it would bind to another molecule. This type of experimental design is called a(n)
A. in vitro observation
B. occupational cohort study
C. age cohort study
D. clinical trial
Answer:
A; in vitro observation
Explanation:
In-vitro is a process in which an experiment/organism is performed/taking place in a test tube or culture dish (controlled environment) outside of a living organism. Since a specific molecule was taken from the yeast cell and placed in a separate environment outside of its original living organism (the yeast cell), it is under in-vitro observation. A good example of in-vitro observation is IVF (in-vitro fertilization), when an egg from a mother and the sperm from a father fertilizes in a test tube outside of the mother's body and conception happens outside the body in a laboratory until it becomes an embryo and is placed back into the mother's body.
Plants exchange gas with the atmosphere. Which statement accurately describes this process?
A. Plants release carbon dioxide and take in oxygen through the stomata in leaves.
B. Plants release oxygen and take in carbon dioxide through the xylem in leaves.
C. Plants release carbon dioxide and take in oxygen through the xylem in leaves.
D. Plants release oxygen and take in carbon dioxide through the stomata in leaves
Answer:
D. Plants release oxygen and take in carbon dioxide through the stomata in leaves.
Explanation:
The stomata are pores in plant tissues that permit gas exchange. Usually, they are found in the leaves but some plants have stomata on their stems.
The stomata allow the plant to take carbon dioxide, needed for photosynthesis, it is like the lungs for the humans.
I hope this answer helps you.
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According to the cladogram shown, which two animal species shared the most recent common ancestor?
A. Primates and crocodiles
B. Birds and rodents
C. Sharks and birds
D. Birds and crocodiles
Answer:
D.
Explanation:
A 'common ancestor' on a cladogram is all of those points where your lines come down and meet the primary line at the bottom.
In this case, your most recent common ancestor is at the point connected to the crocodile. All species at or past that point have that common ancestor, which include only the crocodile and the bird.
Sheath of schwann cell containing cytoplasm is called
Answer:
neurilemma
Explanation:
its surrounds the axon of the neuron
The Schwann cell sheath containing cytoplasm is known as the neurilemma, and it is part of the myelin sheath structure produced by the Schwann cell for insulating axons in the peripheral nervous system.
Explanation:The sheath of Schwann cell containing cytoplasm is called the neurilemma. Schwann cells are a type of glial cell specific to the peripheral nervous system, responsible for the production of the myelin sheath that insulates axons. The myelin sheath, often compared to a pastry wrapped around a hot dog, is tightly wrapped around the axon with little to no cytoplasm between the layers. However, at the outermost layer of the Schwann cell membrane, you can find cytoplasm and the nucleus, forming a bulge on the side of the myelin sheath. The Schwann cell completely encircles a single axon segment, in contrast to oligodendrocytes in the central nervous system, which extend their processes to multiple axon segments.
The nodes of Ranvier are regularly spaced gaps between sections of the myelin sheath along an axon, allowing for rapid transmission of nerve impulses.
A bird species known as the cattle egret is often found near farms in wet areas. The bird waits, sometimes even perched on a cow's back, until the cow kicks up a frog or fish while it walks. Then, the bird strikes and eats the exposed prey. This is an example of what kind of feeding relationship?
A. Detritus
B. Parasitic
C. Mutualistic
D. Herbivorous
Answer:
Mutualistic
Explanation:
Mutualistic relationship may be defined as a type of biological interaction in which both the organism are benefited from each other. This shows a positive type of relationship between the organisms.
The bird cattle egret perch on cow's back and eats the prey that hurdles the cow, in returns the cow provide food to the cattle egret. Hence, they shows mutual type of interaction with each other.
Thus, the correct answer is option (C).
Which of the following terms is defined as a relaxation technique that involves a sensation of heaviness, warmth, and tingling in the limbs? Progressive relaxation Autogenic training Bracing Neuromuscular relaxation
Answer: Autogenic training
Explanation:
Autogenic training is a kind of relaxation technique which can be used to reduce the anxiety. It is a self guided relaxation process, which concentrates over the sensations occurring within the body. This method of training was developed by J. H Schultz. This method creates a feeling of heaviness, which is useful in slowing down the breathing and heartbeat which usually raised during the anxiety. This method also generates a cool sense over the forehead and warmness in the body. The method can be practiced while lying down and sitting.
Most animals and plants reproduce sexually. This means that DNA is passed down to new organisms from two parental organisms. Which of the following is a key advantage of sexual reproduction?
A. The elimination of genetic mutations from a parent organism
B. Increased genetic diversity for changing environments
C. The receipt of the strongest genes from both parents for survival
D. The creation of new genes to improve surviva
B. Increased genetic diversity for changing environments
With sexual reproduction an offspring gets a bit of traits from both parents. This means that there is more variety and diversity. Think about humans. We are very genetically divers. There are people with brown hair or blond or red. People with blue, brown, or green eyes. There are also some people that are short or tall. This goes to show that sexual reproduction increases genetic reproduction.
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Answer:
B
Explanation:
How has biodiversity been affected in areas where green crabs have been introduced?
A. Additional predators have migrated into the area to feed on the crabs, causing an increase in predator diversity.
B. Native shellfish populations have dramatically decreased as they are outcompeted by the crabs, causing a decrease in biodiversity.
C. The amount of predation on crabs by seabirds has gone up, but biodiversity has not been affected.
D. The overall number of crab species has dramatically increased, increasing overall biodiversity.
The correct answer is B) Native shellfish populations have dramatically decreased as they are outcompeted by the crabs, causing a decrease in biodiversity.
Biodiversity has been affected in areas where green crabs have been introduced in that native shellfish populations have dramatically decreased as they are outcompeted by the crabs, causing a decrease in biodiversity.
Green crabs represent a serious threat to biodiversity in the ocean ecosystem because they are predators that feed with animals that are part of the biodiversity such as clams, mussels, and oysters. As the predators they are, they can dramatically change the ecosystem by affecting the living and reproduction of many species.
Identify the accurate statement regarding prenatal development and birth. The development of the central nervous system is completed during the embryonic period. In the last months of prenatal life, the lungs begin to expand and contract and the valves of the heart undergo final maturation. A baby cannot be both preterm and small-for-date. A 36-week fetus will not yet have developed sufficient lung function to survive on its own.
Answer: Option B
Explanation:
The prenatal development of the fetus is very important in order for the fetus to live a healthy life outside the womb.
The vital organs of the fetus must be fully development before delivery of the fetus. The kidney, lungs and brain must be fully developed else the fetus can get exposed to many disease since birth.
The last months of the prenatal development includes the expansion and contraction of valves of heart which undergoes the final maturation.
Consider the following family history: Bob has a genetic condition that affects his skin. Bob’s wife, Eleanor, has normal skin. No one in Eleanor’s family has ever had the skin condition. Bob and Eleanor have a large family. Of their eleven children, all six of their sons have normal skin, but all five of their daughters have the same skin condition as Bob. Based on Bob and Eleanor’s family history, what inheritance pattern does the skin condition most likely follow?
Answer: the correct answer is X-linked dominant.
Explanation:
X-linked dominant is a mode of genetic inheritance in which a dominant gene is carried on the X chromosome.
The inheritance pattern suggested by the family history is X-linked recessive inheritance. The skin condition gene lies on the X chromosome. Hence, daughters inheriting the X chromosome with the defective gene from Bob have the skin condition, while sons who inherit the Y chromosome from Bob do not.
Explanation:Based on Bob and Eleanor's family history, the most plausible inheritance pattern for the skin condition is X-linked recessive inheritance. This means that the gene causing the skin condition is located on the X chromosome. In such a scenario, females (who have two X chromosomes) will develop the skin condition if they inherit the defective gene from both parents. However, in this case, since Eleanor does not carry the defective gene, the daughters who each received an X chromosome with the defective gene from Bob have the skin condition.
Conversely, the sons who received their fathers' Y chromosome instead of the X do not get the skin condition.
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What affect would a damaged thylakoid membrane have on photosynthesis?
A. The damage would affect the flow of electrons through the mitochondria.
B. A damaged thylakoid would affect ATP synthesis.
C. The damage to the thylakoid would affect the splitting of the water molecule.
D. The sodium-potassium pump would be affected by a damaged thylakoid.
Answer:
B
Explanation:
Thylakoid contains proteins chains that are important in photosynthesis – especially the light-dependent phase. The protein chain conveys the high-energy electron harnessing its energy to pump H+ ions across of the membrane to create a proton-motive force. This potential difference in H+ ions is then harnessed by ATP-synthase to synthesize ATPs.
Inside chloroplasts and cyanobacteria, thylakoids are membrane-bound compartments. They are where photosynthesis' light-dependent reactions take place. A thylakoid membrane surrounds a thylakoid lumen in thylakoids. Chloroplast thylakoids typically form grana, which are stacks of discs.
Thylakoids include protein chains that are essential for photosynthesis, particularly during the light-dependent phase. The high-energy electron is conveyed by the protein chain, which uses its energy to pump H+ ions across the membrane and create a proton-motive force. ATP-synthase then uses this potential difference in H+ ions to manufacture ATPs.Thus, the answer is B because the damaged thylakoid will affect ATP synthesis.
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About one year is required in the gymnosperm:
to develop the egg
to grow the male and female cones
between pollination and fertilization
between fertilization and germination
Answer:
between pollination and fertilization
12. Which of these mass movement events is considered a slide?
A. Slump
B. Rock fall
C. Creep
D. Rock avalanche
The correct answer is A. Slump, as it is a type of mass movement where material moves down a slope in a fairly coherent mass known as a slide.
Explanation:The question pertains to which of the listed mass movement events is considered a slide. A slide is a type of mass movement where material moves down a slope in a fairly coherent mass. This contrasts with a flow, where material mixes and moves more fluidly, or a fall, where material free falls or bounces down a slope. When referring to the types of mass movement: Based on these definitions, the correct answer to the question is A. Slump, as it is characterized by a downward and outward movement of slope material and can be described as a type of slide.
Final answer:
A slump is considered a slide and is a coherent block of material moving along a curved surface, typically triggered by natural events like earthquakes and volcanic eruptions. Understanding these events is essential for risk mitigation.
Explanation:
The correct option that identifies a type of mass movement event considered a slide is A. Slump. A slump is a form of mass movement where material moves downslope as a coherent block along a curved surface. This event involves the downward and outward movement of soil or rock on a slope and is typically triggered by natural causes such as earthquakes, volcanic eruptions, and excessive water saturation due to heavy rains or melting snow. Other types of mass movements include rock falls, which involve the freefall of rocks, and creep, which is a very slow downslope movement of soil or rock.
Understanding mass wasting and its triggers is crucial for evaluating the risks associated with such geological events and for implementing measures to mitigate these risks and protect human lives and infrastructure.
100 points!! What is the effect of climate change on animals?
Renin, released from the kidney as a result of a decrease in blood pressure, acts on ________ produced in the liver. This triggers a series of reactions that culminate in the production of _______ in the adrenal glands.
Answer:
angiotensinogen and aldosterone
Explanation:
Renin, released from the kidney as a result of a decrease in blood pressure, acts on angiotensinogen produced in the liver. This triggers a series of reactions that culminate in the production of aldosterone in the adrenal glands.
You're moving into a new apartment and trying to fit your large chair through the doorway. Your friend, who is helping you move, suggests rotating the chair a different way and seeing if it fits. However, you remember that the last time you moved the chair, it must first be reclined in order to fit through the doorway. Which choice below correctly identifies the learning strategies that you each are using in this example?
A. Your friend is demonstrating insight, and you're demonstrating imprinting.
B. Your friend is demonstrating trial-and-error, and you're demonstrating imprinting.
C. Your friend is demonstrating trial-and-error, and you're demonstrating insight.
D. Your friend is demonstrating insight, and you're demonstrating trial-and-error
Your friend is demonstrating trial-and-error. They would try different angles until one allows the chair to go through. You are demonstrating insight. This means that you are taking what you learned in a similar situation, and using it to respond to this situation. You had already done this before and try to reenact what had worked previously.
That makes the answer to this question C.
Hope this helped!
~Just a girl in love with Shawn Mendes
Answer:
C. Your friend is demonstrating trial-and-error, and you're demonstrating insight.
Explanation:
Insight means that you have an understanding and knowledge about the subject in a inner way, that you know more deeply the matter, and in this case as you have previous knowledge from when you tried to move the chair in the past, and now you know how to do it, while your friend is trying a new way to do it based on a trial and error, since the first way didn´t work, now he wants to rotate it since he thinks that is the next logical step.
Which of the following is the correct sequence of events in phagocytosis?
A) chemotaxis, ingestion, digestion, adherence, killing
B) ingestion, adherence, chemotaxis, digestion, killing
C) adherence, digestion, killing, ingestion, chemotaxis
D) chemotaxis, adherence, ingestion, digestion, killin
Answer:
B
Explanation:
i'm pretty sure
Pregnant women generally need to take a supplement that contains
Answer:
Basically most women take prenatal vitamins such as 400mcg of folic acid 400IU of vitamin d 200 to 300 mg of calcium etc...
Explanation:
folic acid is important for certain function of the body
vitamin d is important to prevent rickits and the absorption of calcium
finally calcium is responsible for the enzymes in the body
hope that helps
Pregnant women generally need to take a supplement that contains folic acid to aid in the healthy development of the neural tube in a fetus and prevent neural tube defects. Other important nutrients include thyrotropin, prolactin and parathyroid hormone. A balanced diet and controlled calorie intake are also crucial during pregnancy.
Explanation:Pregnant women generally need to take a supplement that contains folic acid, one of the B vitamins which is important for healthy development of the neural tube in a fetus. Insufficient folate in the early stages of pregnancy can cause neural tube defects such as spina bifida, in which spinal tissue protrudes through the newborn's vertebral column, which has not entirely closed. This problem arises due to the failure of the neural tube to close rightly.
Other key nutrients required during pregnancy include thyrotropin, prolactin, adrenocorticotropic hormone (ACTH), and increased parathyroid levels. These provide necessary materials for the growing fetus and help maintain the mother's health. It's important to consult with a health care provider for individual recommendations based on specific health needs.
Further, a healthy diet filled with leafy greens, whole wheat, fruits, nuts, and legumes can also help provide the necessary nutrients during pregnancy. Also, while the mother's appetite increases during the pregnancy, only an additional 300 calories per day are required to integrate the growing fetus during the second and third trimesters.
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Characid fishes are found naturally only in South America and Africa. Fossils of these fish are not found on any other continents. What is the most likely explanation of this distribution pattern? A These fishes arose in either Africa or South America and migrated across the South Atlantic Ocean to the other continent. B Characid fishes arose in the South Atlantic Ocean and migrated to Africa and South America. C Convergent evolution is responsible for the distribution of characid fishes. D Characid fishes arose prior to the separation of the African and South American continents.
Answer: the correct answer is D. Characid fishes arose prior to the separation of the African and south American continents.
The likely explanation for characid fishes being found only in South America and Africa is that they evolved before the continents separated, a fact supported by biogeographical patterns related to historical continental drift. Adaptive radiation, while not the direct cause of their distribution, is a process of rapid species diversification seen in similar fish populations like the cichlids of Lake Victoria.
Explanation:The distribution pattern of characid fishes being found naturally only in South America and Africa, with fossils not found on other continents, is most likely explained by the historical division of landmasses due to tectonic plate movement. This distribution pattern is consistent with biogeographical evidence that suggests these fishes arose prior to the separation of the African and South American continents - when they were part of the ancient supercontinent Gondwana. This is in line with the principle that broad groups which evolved before the breakup of supercontinent Pangaea (around 200 million years ago) are now distributed worldwide, whereas groups that evolved subsequently are often unique to specific regions.
Moreover, the concept of adaptive radiation is relevant here, but not in the direct explanation of the characid fishes' distribution. Adaptive radiation refers to the process where a species rapidly evolves into many new species, filling different ecological niches. An example of this is the cichlid fishes in Lake Victoria, which underwent a spectacular adaptive radiation, diversifying into hundreds of species with specialized feeding strategies and morphologies within a relatively short period of time, as documented by biologists in the 1980s.
A dog breeder wishes to develop a breed that does not bark. She starts with a diverse mixture of dogs. Generation after generation, she allows only the quietest dogs to breed. After 30 years of work she has a new breed of dog with interesting traits, but on average, the dogs still bark at about the same rate as other dog breeds. Which of the following would be a logical explanation for her failure?
A. There is no variation for the trait (barking).
B. The tendency to bark is not a heritable trait.
C. The selection was artificial, not natural, so it did not produce evolutionary change.
D. There was no selection (differential reproductive success) related to barking behavior.
Answer: Option B
Explanation: There are basically two types of traits. Acquired and inherited traits.
Acquired traits: The traits that is acquired from the environment and cannot be inherited from one generation to another generation is known as acquired trait.
Such as time of barking, time of sleeping, amount of food that one animal eats.
Inherited traits: The traits that can be transferred from one generation to another generation is known as Inherited traits.
Example: fur color, height, eye color.
So, the condition here is rate of barking which is not a heritable trait and cannot transferred from one generation to another even by breeding for several generations(option B ).
A forest contains both spruce trees and pine trees. Young spruce trees need shade in order to mature. Young pine trees need full sunlight in order to mature. How do spruce trees most likely affect the environment's carrying capacity for pine trees?
A. Spruce trees reduce the sunlight available to young pine trees, thus decreasing the environment's carrying capacity for pine trees.
B. Spruce trees help young pine trees adapt to growing in shade, thus increasing the environment's carrying capacity for pine trees.
C. Spruce trees prevent other trees from competing with pine trees, thus increasing the environment's carrying capacity for pine trees.
D. Spruce trees encourage the growth of other trees that need sunlight, thus decreasing the environment's carrying capacity for pine trees.
Answer: A. Spruce trees reduce the sunlight available to young pine trees, thus decreasing the environment's carrying capacity for pine trees.
Explanation:
Carrying capacity is the maximum number of the members of the population of a species which an ecosystem can sustain in terms of availing the resources. The population size will be affected when the carrying capacity does not meet the demand of the population.
In the given situation, the pine trees requires the sunlight to mature whereas the spruce trees requires the shade to get mature. If the spruce trees are taller than the pine trees they are likely to reduce the available sunlight of the young pine trees. Hence, the environmental carrying capacity for pine trees will decrease in the absence of proper sunlight.
The ____________ describes a species as groups of organisms that interbreed, have a shared ____________ , and are reproductively isolated from all other species.
Answer:
1. Biological species concept
2. Gene pool
Explanation:
Biological species concept defines the species as a group of individuals that can interbreed to produce fertile progeny. The individuals from two different species cannot interbreed and produce viable and fertile progeny. This means that two species are reproductively isolated from each other.
The total number of genes and alleles present in the individuals of a species makes its gene pool. Each species has its unique gene pool.
Which gland is called the emergency gland and helps the body adjust to stress?
Answer:
Adrenal gland is known as emergency gland which helps the body to adjust to the stress.
Explanation:
Adrenal gland secretes a hormone which is known as adrenaline hormone which is called as emergency hormone. When adrenaline is secreted into the blood it prepares our body of action. This hormone rapidly responds to stress by increasing our heart rate and rushing blood to muscles and brain.
Clinical trials model the effects of new drugs on human society. Which of the
following is used to avoid bias in a clinical trial of a new drug?
A. High self-confidence
B. Data manipulation
C. Double-blind testing
D. Personal interest
Answer:
Double-blind testing - C.
Double-blind testing is used to avoid bias in clinical trials for new drugs. Neither the participants nor researchers know who is receiving the new drug or a placebo, eliminating potential biases.
Explanation:The correct method to avoid bias in a new drug's clinical trial is double-blind testing. In a double-blind trial, neither the participants nor the researchers know who is receiving the new drug or a placebo, until the study is completed. This approach eliminates biases that might affect the results, such as the placebo effect, where a participant's symptom's might improve simply because they believe they are receiving medication, or researcher bias, where researchers might inadvertently influence the participants or interpret the results in a way that favors the new drug.
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what affect would a damaged thlaykoid membrane have on photosynthesis
Answer:
dark reaction
Explanation:
The dark reactions then occur outside the thylakoid. In these reactions, the energy from ATP and NADPH is used to fix carbon dioxide (CO2). The products of this reaction are sugar molecules and various other organic molecules necessary for cell function and metabolism.
______ act as a barrier to invading cells and viruses. muscle cells connective tissue epithelial cells none of the above
Answer:
Epithelial cells
Explanation:
Epithelial cells act as a barrier to invading cells and viruses.
It lines the tissues of blood vessels in order to keep blood flowing and keeping you healthy.
They discover that the chemical energy in the glucose produced added to the energy used to split water to make oxygen and to the heat lost in the process is equal to the energy of sunlight that was captured by chlorophyll. This is an illustration of what?
Answer:
Photosynthesis
Explanation:
Photosynthesis is a process performed by producing organisms in which the capture of solar energy and its transformation into chemical energy is observed.
Photosynthesis means synthesis by light, the process by which plants, algae and some bacteria use light energy to produce organic matter. Photosynthesis is the main means of energy production of autotrophic beings. This process usually uses carbon dioxide (CO2) and water (H2O) to produce organic matter in the form of glycids, which will serve as food for the body, also releasing oxygen gas (O2) to the atmosphere in the process. Virtually all the oxygen that makes up Earth's present atmosphere is the result of photosynthesis.
Photosynthesis is a long and complex process and it is in it that the chemical energy in glucose produced added to the energy used to divide water to produce oxygen and for the heat lost in the process is equal to the energy of sunlight that was captured by chlorophyll.
Animals must digest food once it's consumed. The diagram shows the steps involved in which type of digestion?
A. Intracellular digestion
B. Extracellular digestion
C. Acid mediated digestion
D. Digestive tract absorption
Answer:
A. Intracellular Digestion
Explanation:
Intracellular digestion. Intracellular digestion is the type of digestion which takes place in the cell cytoplasm
Answer:
The correct answer is option A. intracellular digestion.
Explanation:
The diagram is given in question showing the steps involved in intracellular digestion which is the breaking of food or other substances in the cytoplasm of a cell by engulfing from surroundings.
In the following diagram Type of intracellular digestion that is phagocytosis is shown, the engulfed particle pinched off by lysosomes having hydrolytic enzymes. The food particles present within the phagosome is then digested by the lysosome's enzymes.
Thus, the correct answer is option A. intracellular digestion.