Two closely related populations of mice have been separated for many generations by a river. Climatic change causes the river to dry up, thereby bringing the mice populations back into contact in a zone of overlap. Which of the following is not a possible outcome when they meet?
A) They interbreed freely and produce fertile hybrid offspring.
B) They no longer attempt to interbreed.
C) They interbreed in the region of overlap, producing an inferior hybrid. Subsequent interbreeding between inferior hybrids produces progressively superior hybrids over several generations.
D) They remain separate in the extremes of their ranges but develop a persistent hybrid zone in the area of overlap.
E) They interbreed in the region of overlap, but produce sterile offspring

The correct answer is B) they no longer attempt to interbreed.

Explanation:

This question speaks to Speciation and Natural Selection.

What is a species? A species is a group of organisms that are theoretically able to interbreed in order to produce viable offspring.

We say "theoretically," because members of the same species might be geographically isolated (on an island, for example) and yet, if they were able to get together, they could successfully mate because they are wild animals.

A "population" is a subset of a species, and is comprised of organisms of the same species but which live in close proximity and interact with each other, and therefore have an actual chance of mating.

If members of different species attempt to interbreed, the result is usually null.

A species, by definition, is reproductively isolated from other species.

Occasionally, a sterile hybrid can form if closely related species mate.

For example, horses and donkeys are two different, but closely related, species. Horses and donkeys can interbreed, but their offspring, mules, are sterile.

Cheers!

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.