Question

question 8 of 10
the graph below shows the population of mice in an ecosystem where the mice are not allowed to enter or leave.
mouse population
graph with population size on y - axis, time on x - axis, curve with points a, b, c, d
which best describes the population at point a?
a. the death rate is higher than the birthrate

Explanation:

Step1: Analyze the graph type

The graph is a logistic growth curve (S - shaped curve) for the mouse population over time. In a logistic growth model, the population growth rate changes with population size. At the early stage (point A), the population is small, and resources (like food, space) are relatively abundant.

Step2: Analyze birth and death rates at point A

In the early phase of logistic growth (before reaching the carrying capacity), when the population size is low (point A), the birth rate is higher than the death rate because there are enough resources to support reproduction, and competition for resources is low. Option A says the death rate is higher than the birth rate, which is incorrect for point A in a logistic growth curve. (Assuming other options, for example, if there was an option like "The birth rate is higher than the death rate and population is growing slowly as size is small", that would be correct. But since we analyze option A: at point A, population is increasing (as the curve is rising), so birth rate > death rate, so A is wrong. But since the question is about describing point A, and we need to evaluate option A. )

Answer:

Option A is incorrect. At point A (early stage of logistic growth), the population size is small, resources are abundant, so the birth rate is higher than the death rate, and the population is growing (though maybe slowly at the start of the curve). So the statement in option A ("The death rate is higher than the birthrate") does not describe point A. If we were to choose the correct description, it would be that the birth rate exceeds the death rate and the population is growing (with low population density and abundant resources). But for the given option A, it is incorrect.