9. Prior to herbicide application, a student notes that there are two related species of weeds (A and B) that occur in similar numbers in plot 5. Species A reproduces sexually and species B reproduces asexually. After exposing both weed populations to several applications of the herbicide, the student observes that the population of species B has become significantly smaller than the population of species A.

Why did species A most likely have a survival advantage over species B?

A,There was greater genetic variability in species A than there was in species
B. The percentage of herbicide-resistant weeds decreased in species A but not in species B.
C. Asexual reproduction allows the weeds to produce more offspring in a shorter period of time.
D. Sexually reproducing weeds are better able to utilize nutrients from the herbicides than asexually reproducing weeds.

To determine why species A most likely had a survival advantage over species B, we need to consider the given information. We know that prior to herbicide application, the two species of weeds occurred in similar numbers in plot 5. However, after several applications of the herbicide, the population of species B became significantly smaller than the population of species A.

Looking at the answer choices:

A. There was greater genetic variability in species A than there was in species B.
This choice suggests that species A had a survival advantage because it possessed greater genetic variability. Genetic variability allows a species to adapt and evolve, increasing its chances of survival. However, we do not have any information about the genetic variability of the two species, so we cannot determine if this is the correct answer.

B. The percentage of herbicide-resistant weeds decreased in species A but not in species B.
This choice suggests that species A had a survival advantage because the percentage of herbicide-resistant weeds decreased in species A. This means that a higher proportion of species A were able to survive the herbicide treatment. This could be due to genetic factors that make species A more resistant to the herbicide. However, we do not have any information about herbicide resistance in the two species, so we cannot determine if this is the correct answer.

C. Asexual reproduction allows the weeds to produce more offspring in a shorter period of time.
This choice suggests that species B had a survival advantage because asexual reproduction allows for the production of more offspring in a shorter period of time. However, the question states that the population of species B became significantly smaller than the population of species A. So, this choice does not explain why species A had a survival advantage.

D. Sexually reproducing weeds are better able to utilize nutrients from the herbicides than asexually reproducing weeds.
This choice suggests that species A had a survival advantage because sexually reproducing weeds are better able to utilize nutrients from the herbicides compared to asexually reproducing weeds. However, there is no information given about the ability of the two species to utilize nutrients from the herbicides, so we cannot determine if this is the correct answer.

Based on the given information and the analysis of the answer choices, it is difficult to determine the exact reason why species A had a survival advantage over species B. Additional information about the genetic variability, herbicide resistance, and nutrient utilization of the two species would be necessary to make a definitive conclusion.