Improved nutrition, medical treatment, and sanitation all help account for the dramatic increase in ___________ in the twentieth century.
a. the life expectancy crossover
b. functional age
c. active living age
d. average life expectancy

Answers

Answer 1
I think the answer would be D.

Related Questions

What is the muscular organ that holds the developing embryo?

Answers

It's the uterus
hope this helped

"owls eat rats, mice, shrews, and small birds. assume that, over a period of time, an owl consumes 5,000 j of animal material. the owl loses 2,300 j in feces and owl pellets and uses 2,500 j for cellular respiration. what is the production efficiency of this owl?"

Answers

Answer: 4%

Out of 5000kcal, the owl loses 2300kcal which mean it could only process 2700kcal. Out of 2700kcal processed, 2500 kcal is used for cellular respiration so there is 200 kcal used to make body cells. The production efficiency would be: 200kcal/5000kcal= 4%

Which product of combustion contributes most to the greenhouse effect?

Answers

Carbon Dioxide is the gas that contributes most to the greenhouse effect.

the fittest organisms in an environment survive and reproduce what is the name for this process

Answers

To answer your question the name of this process is, Natural Selection.

Final answer:

The process by which the fittest organisms in an environment survive and reproduce is called natural selection, which is central to the theory of evolution. It's not just the fittest but those with relative fitness to their environment who may survive and reproduce, resulting in their traits becoming more common in the population.

Explanation:

The name for the process where the fittest organisms in an environment survive and reproduce is known as natural selection. This is a fundamental concept of biology and a critical mechanism of evolution. Natural selection, also referred to colloquially as survival of the fittest, occurs when individuals with favorable traits are more likely to survive environmental changes and therefore reproduce more prolifically than those without such traits, leading to these advantageous traits becoming more common in the population over time.

It is a common misconception that only the very fittest organisms survive and reproduce. In reality, fitness is relative to the specific environmental conditions and includes a diverse range of traits, some individuals who may not seem as fit can still survive and reproduce. This variation in success is influenced by many factors, such as food availability, predator presence, and mating preferences.

Charles Darwin termed the phrase 'fitness' to describe an organism's ability to survive and reproduce. His observations and those of Alfred Russel Wallace lead to the establishment of the theory of evolution by natural selection, where nature selects the variations most useful for survival in given conditions. An example of this is the giant tortoises of the Galapagos Islands, where tortoises with longer necks were more apt to survive during droughts because they could reach more food.

The Sun is

A.
the same size as all the other stars.
B.
the largest star in the universe.
C.
a very small star.
D.
a medium-sized star.

Answers

D a medium sized star because the largest star is canis majoris and the smallest star is brown dwarf..☺

Answer:

The answer is d)a medium-sized star

Explanation:

The Sun is the star that is closest to Earth and although its size is 100 times larger than Earth, it is a medium-sized star when compared to other stars. Thanks to the Sun, life on Earth is possible. The Sun exerts a great force of gravitational attraction on all the planets, which causes them to revolve around it.

Molecules tend to move from an area of high concentration to an area of low concentration in a process known as

Answers

in a process known as diffusion. For example, spraying a can of deodorant.

An example of natural selection is the tail of a male peacock. The females of the species choose mates based on the colors of the males’ tail feathers. If females begin using different criteria than feather color when they choose mates, what would most likely happen to the tails of peacocks over time?

increased variation in tail feather color because the selection pressure has been relieved
increased variation in tail feather color because the peacocks try different ways to impress the females
decreased variation in tail feather color because no form of the trait is advantageous
decreased variation in tail feather color because the only reason for variation was selection pressure

Answers

The correct answer is the last one: Decreased variation in tail feather color because the only reason for variation was selection pressure.

If the female peacock were to base her selection criteria on something other than the colors of the male's tail feathers, the latter would not play such an important role anymore and therefore there would no longer be the pressure of needing to have the brightest, most variant and vibrant colors. 
The female peacock will be based in her selection no through the color of the tail of the male. So if females begin using different criteria than feather color when they choose mates, the event that ould most likely happen to the tails of peacocks over time is decreased variation in tail feather color because the only reason for variation was selection pressure.

Many farmers in less densely populated areas, such as amazonia, practice _______________, also known as shifting cultivation or swidden agriculture where an area is cleared and then burned for the vegetative remains to release nutrients back into the soil.

Answers

Many farmers in less densely populated area, such as Amazonia, practice slash and burn agriculture, also known as shifting cultivation or swidden agriculture where an area is cleared and then burned for the vegetative remains to release nutrients back into the soil. Shifting cultivation is a system where a farmer uses a piece of land, only to abandon or alter the initial use a short time later. Advantages of shifting cultivation includes; enhance control of pest and disease, inorganic matter addition which provide nutrient to crop, an effective way of weed control

Compared with people who do not have schizophrenia, synaptic pruning occurs __________ in people who do have the disorder.

Answers

Answer: At a faster rate

Synaptic pruning is a process of brain pruning the unused synapse so it can strengthen the used one. This process happens once in maturing children. 
It seems that the pruning is excessive in the schizophrenia patient, makes the brain synapses disrupted.

The eastern meadowlark and the western meadowlark are two closely related bird species. the two species avoid interbreeding because they have different mating songs. this is an example of -

Answers

The answer is behavioral isolation

The answer is behavioral isolation

The major source of imbalance in the carbon cycle is the result of

A) human activities.

B) changes in Earth's orbit.

C) increased volcanic activity.

D) changes in weather patterns.

Answers

I think it would be either A or B but I am not sure.... If anything I think I would go with A.
Hope this helps 

Although estrogen is primarily produced by ovaries, it is also produced by the adrenal glands and in fat tissue. loss of the normal amount of fat lowers the level of estrogen so that the menstrual cycle and ovulation stops. female olympic athletes who train severely often shut off their cycles. what would be a reasonable evolutionary cause of this shutdown?

Answers

When the cells are provided with oxygen

Final answer:

The shutdown of the menstrual cycle and ovulation in female athletes with low body fat and estrogen levels is an evolved adaptation to prevent pregnancy during times of physical stress or low energy reserves, as a way to conserve energy and ensure the mother has sufficient resources for a successful pregnancy.

Explanation:

The evolutionary cause of the shutdown of the menstrual cycle and ovulation in female Olympic athletes who train severely and experience a significant loss of body fat can be understood as a protective mechanism. The body requires a considerable amount of resources to maintain a pregnancy, and during periods of extreme physical stress or when energy reserves are low, it may not be advantageous for reproduction to occur.

If the body senses that it is not in an optimal state for supporting a pregnancy due to low levels of estrogen and fat tissue, it may shut down the reproductive cycle to conserve energy and prevent a pregnancy that could be risky for both the mother and potential offspring.

This response is likely an evolved adaptation to increase overall reproductive success by ensuring that pregnancy occurs only during times when the mother has sufficient resources to support both herself and the developing fetus.

Which method will most accurately determine the diversity of an ecosystem?

Answers

D. Mangrove tree crab

The correct answer is D. Mangrove tree crab.

In the given food chain of a mangrove community, green algae are producers, fish is primary consumer as they feed on green algae, mangrove tree crab is secondary consumer feeding on fish, mangrove water snake is tertiary consumer which feeds of mangrove tree crabs and finally American crocodile is top consumer which feeds on snakes. In this food relationship, if the number of mangrove water snake increase, the population of mangrove tree crab will decrease as crab would be eaten by more snakes. But in the long the decrease mangrove tree crab, the population of mangrove water snake will also decrease in want of food.

Homeostasis is the process of maintaining a stable internal environment in the body. what is the term that defines the targeted value to be maintained?

Answers

The answer is "set point"

What is evolution? what are the pieces of evidence scientists use to study evolution?

Answers

evolution is the development of species over time. scientists can study fossils for evidence of evolution

Answer:

Evolution is how living things change over time and how new species develop. Scientists can study fossils for evidence.

Explanation:

HIV acts by attaching to receptors on the surfaces of T-cells that aid other lymphocytes in fighting infection. Once HIV is inside a cell, its RNA is reverse-transcribed and its product DNA is integrated into the host cell. It then directs the production of new virus particles. As time goes on the number of T-cells A) increases. B) decreases. C) stays the same. D) is unpredictable.

Answers

HIV acts by attaching to receptors on the surfaces of T-cells that aid other lymphocytes in fighting infection. Once HIV is inside a cell, its RNA is reverse-transcribed and its product DNA is integrated into the host cell. It then directs the production of new virus particles. As time goes on the number of T-cells B) decreases.

Answer:

B) decreases.

Explanation:

    The HIV virus acts within the cells of the immune system, responsible for the body's defense. After entering the cell, HIV begins to act and integrate into the genetic code of the infected cell. The cells most affected by the virus are called T-CD4, which are used by HIV to make copies of itself.

    Each time this cell, when infected, divides, it produces a copy of its genetic code and, at the same time, a copy of the virus's genetic code.

    Infected by the virus, the cells of the immune system begin to function less efficiently until, over time, the body's ability to fight common diseases diminishes and is subject to the onset of opportunistic diseases.

What could be an additional trial to determine the effect of salt on plant growth

Answers

Three main traits are involved in salt tolerance: ion exclusion, tissue tolerance and osmotic tolerance.


Numerous genes encoding salt tolerance traits are likely to contribute to crop performance.


A compilation of transgenes and their effects on salt tolerance traits in crops is presented.


Temporal and spatial control of gene-expression are often important for increasing tolerance.


Quantifying yields in saline soils, and using proper controls in field trials, can guide crop improvement programs.

Why are humans important to the life cycle of malaria parasites?

Answers

The malaria parasite life cycle involves two hosts. During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host .

_____ is a special case of explosive speciation in which new species form rapidly in response to numerous "open" ecological niches. peripatric speciation adaptive radiation allopatric speciation co-speciation sympatric speciation

Answers

Adaptive radiation is a special case of edplosive speciation in which new species form rapidly in response to numerous "open" ecological niches 

Final answer:

Adaptive radiation is a form of rapid speciation where new species evolve to fill different ecological niches, often after a mass disaster or colonization event provides access to new resources.

Explanation:

Adaptive radiation is a special case of explosive speciation in which new species form rapidly in response to numerous "open" ecological niches. It involves the relatively rapid evolution from a single species to several species to fill a diversity of available ecological niches.

Examples include the cichlid fish in East Africa's lakes and Darwin's finches in the Galapagos, where a population experiences speciation following a mass disaster or colonization of a new area with diverse habitats. These events provide access to a range of unexploited resources and niches, leading to the diversification of the species.

The daily value for protein is ____ grams per day.

Answers

56 grams per day for men, but really varies based on weight, age, and other factors.

When species interact, as fungi and algae do in lichen, so that the interaction of the two species increases the fitness of both species, this is called __________?

Answers

Mycorrhizae is the scientific term that I believe is the answer. It’s also called a mutualisation relationship.

which organ is involved in ingestion

Answers

Digestion starts in the "mouth" and continues in the stomach. The small intestine completes the digestion process.

Answer:

The mouth is the organ involved in ingestion in the digestive system.

Explanation:

Intake of food into the mouth and break down into small pieces there, is the process of the ingestion. In the ingestion process food is taken into the mouth and crushed and broken down into smaller pieces with the help of teeth. The presence of food triggers nervous reflexes to cause the salivary glands to release a fluid saliva. Saliva also softens and provides moisture to the food in the mouth to make it easier to swallow down to esophagus. It helps in digestion of starches to begin, present in food.

The spoon is too hot after sitting in the hot soup. is this an example of conduction, convection, or radiation? why?

Answers

it is conduction because the molecules in the spoon that become hot from contact with the soup then make other molecules hot, until the whole spoon is hot

Techno and electronica are performed at dancing events known as

Answers

Raves?
I go to raves and that's pretty much all they play. Techno, electronica, EDM, and dance.
Final answer:

Techno and electronica are performed at dancing events known as raves.

Explanation:

Techno and electronica are performed at dancing events known as raves. Raves are high-energy gatherings where people gather to dance and enjoy electronic music. These events often feature DJs and live performances, creating an immersive and energetic atmosphere.

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What does your circulatory system have in common with your nervous system

Answers

both are attached/ connected through the organ and bodily function control

Answer:

Both systems are run throughout the entire body.

Explanation:

What is the specific function of the structure labeled f?basic motor reflex pathways.what is the specific function of the structure labeled f?basic motor reflex pathways.determination of muscle tension increasing tension of the surrounding muscle increasing tension of the antagonistic muscle determination of muscle length?

Answers

Final answer:

Motor reflex pathways, the structure labeled f, regulates reflex reactions to stimuli like physical contact, maintaining muscle length, and adjusting muscle tension according to these sensory inputs.

Explanation:

The specific function of the structure labeled f, the basic motor reflex pathways, refers to the mechanism that allows for reflex actions to occur. This includes the motor neuron pathway linking the sensory fibers in the spinal cord to the muscle. When a stimulus prompts a reflex action, such as a muscle stretch, the motor neuron of the muscle communicates this stimuli, triggering a response. For instance, when your knee is struck with a rubber hammer during a physical exam, the stretch reflex activates a muscle spindle receptor, causing the direct contraction of your muscles. Essentially, these pathways help to maintain muscle length and regulate muscle tension.

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Lichen is a symbiotic decomposer that attachers itself to trees and slowly breaks them down. they obtain nutrients from the tree, allowing them to survive and reproduce. what type of relationship is this?

Answers

This type of relationship is called Parasitism 
Parasitism is a type of symbiotic relationship, or a long-term relationship between two species, where one of the organism, the parasite,gains benefits that come at the expense of the host member. Examples of parasitism includes; Fleas or ticks that live on dogs and cats are parasites. In the above question; Lichen is the parasite and the tree is the host. 

Severe edema in pregnant women may be a symptom of what health condition?

Answers

It could be a sign of preeclampsia, which is pregnancy condition characterized by high blood pressure and signs of damage to the liver and kidneys.
Edema or the swelling is usually a normal condition in pregnancy which occurs because of the excess fluid that collects in body tissues (retention of water), especially  in ankles and feet.

Is an intentional burn that removes fuel and oxygen from an advancing fire?

Answers

it is called backfire

Poisonous substances produced by some microorganisms are called

Answers

Poisonous substances produced by some microorganisms are called microbial toxins.
Microbial toxins are produced by bacteria and fungi and those toxins promote infection by directly damaging host tissues. Also, toxins may cause a disease by disabling the immune system.  Microbial toxins can have important uses in medical science and research, but their effect also may be dangerous (for example, neurotoxin such as Botulinum).
Final answer:

Microorganisms produce poisonous substances known as toxins. These include endotoxins and exotoxins, which are involved in the pathogen's ability to invade and damage body tissues. Remarkable examples are the mycotoxins produced by molds and the potent toxins produced by Bacillus anthracis.

Explanation:

Poisonous substances produced by certain microorganisms are referred to as toxins. These toxins can be categorized further into endotoxins and exotoxins. They facilitate the ability of the pathogen to invade and cause damage to the host body, a characteristic called toxigenicity.

For instance, molds, a type of fungi, produce poisonous substances called mycotoxins. In bacterial microorganisms, some produce virulent factors to evade the immune system, including the M protein found in the fimbriae of certain Streptococcus species or the protective mycolic acid coat produced by Mycobacterium tuberculosis.

Pathogens such as Bacillus anthracis, responsible for anthrax, release potent toxins causing severe symptoms like edema, hypoxia, necrosis and eventually can lead to patient's death if untreated properly.

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