A population of 400 squirrels, living in ideal conditions, has a birth rate of 50 squirrels and a death rate of 40 squirrels per generation.

Increases.

Explanation:

There are 10 squirrels increases per generation if the birth rate is 50 squirrels and a death rate is 40 squirrels. There is slow increase occur in the population of squirrel due to more birth rate as compared to death rate. If the birth rate is equal to death rate, no increase occur in the population while on the other hand, decrease occur in the population, if the birth rate is lower than death rate so according to the given data, the population of squirrel increases.

not sure but try c two haploid cells

explanation:

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.