Question

nt population, doubles ower reproduction.
doubling time
what can we say about their growth rates using the rule o
70?
species y has the same growth rate as species x.
species x has a lower growth rate than species y.
species x has a higher growth rate than species y.

Explanation:

The Rule of 70 states that the doubling time ($T_d$) is approximately $\frac{70}{r}$, where $r$ is the growth rate (in percentage). If we assume (from the "Doubling Time" context) that Species X has a shorter doubling time than Species Y (or vice - versa, but the logic is about the inverse relationship between doubling time and growth rate), a shorter doubling time means a higher growth rate (since $T_d\propto\frac{1}{r}$). So if Species X has a higher growth rate, it would double faster. The option "Species X has a higher growth rate than Species Y" is correct as per the inverse relationship between doubling time and growth rate from the Rule of 70.

Answer:

Species X has a higher growth rate than Species Y.