Which one of the following is a population?

Q. Consider the following statements:
A. In the Tundra region, animals have thick fur and thick skin.
B. Most of the animals in grasslands are herbivores.
C. In tropical rain forests, many animals live on trees.
Which of the following best explains these statements?

Q.

The forest department conducted a survey for two types of trees oak and pine in the years 2005, 2008 and 2011. The data obtained is shown below.

The year in which the no. of pine trees is more than oak trees is:

Q. There are multiple color phenotypes in a hypothetical population of beetles living in a New England forest, matching the various colors of the bark of the trees on which they live and hide from predators.
The diagrams below show four possible changes to the population of beetles after air pollution from a coal-burning power plant darkens the bark of the trees in the forest.
Which of the following diagrams represents the most probable change in the coloration of the beetle population in response to the effects of the air pollution?

Q. Statement A: In a forest, all animals and plants are dependent on each other in some way.
Statement B: Forest is an ecosystem.

Q. One can not find the age of a tree by its rings if that tree is located in which of the following forests?