A biologist conducting a long-term field study noticed there were two types of mice in a valley. One type of mouse had webbed toes, and one type of mouse lacked webbed toes. A dam was built in the valley turning the land into a wetland. As the years passed, all mice living in the valley were found to have webbed toes. No mice were found with non-webbed toes.
Which statement best explains the observed change in the mouse population?
a. The mice grew webbing to move more efficiently in the new environment.
b. Webbed-toed mice survived better and reproduced more than mice without webbed toes.
c. Webbed toes in mice are controlled by the environment.
d. The increased water levels in the valley increased the mutation rate in the mouse population.

b. Webbed-toed mice survived better and reproduced more than mice without webbed toes.

Explanation:

Natural selection is a phenomenon that suggests that organisms that have a better structural and morphological advantage over the others have better chances of survival over the others.

The webbed toed mice have a survival advantage over the without the webbed toes because this can help the webbed toed mice to swim. The webbed toed trait will be beneficial and passed on to the next generation of the mice and the webbed toed mice will reproduce more than the mice without webbed toes.

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.