Question

read this passage about two inherited traits in barnyard grass plants.
barnyard grass is a weed that often grows in rice fields. a barnyard grass seedling can have upright leaves that stick straight up or drooping leaves that curl down.
rice seedlings have upright leaves. so farmers weeding their rice fields by hand are more likely to mistake barnyard grass seedlings with upright leaves for rice plants. farmers are more likely to recognize and remove barnyard grass seedlings with drooping leaves.
the graphs below describe leaf type in an isolated population of barnyard grass plants at the start and end of a time period long enough for natural selection to occur. at the start of this time period, the barnyard grass plants environment changed.
describe how the barnyard grass plant population changed over this time period. use the theory of natural selection to construct a possible explanation for this change.
the percentage of grass plants with upright leaves in the population. this suggests that grass plants with upright leaves were increased ly to survive and reproduce than grass plants with drooping leaves. 1 decreased pcurred because there were farmers weeding the rice fields by hand after the populations environment changed. so grass plants with drooping leaves were likely to be removed by farmers.

Explanation:

Natural selection is the process where organisms better adapted to their environment tend to survive and reproduce more. Here, barnyard grass with upright leaves was less likely to be removed by farmers (as rice has upright leaves). So, over time, the proportion of upright - leafed barnyard grass increased. The increase in upright - leafed plants (from 9% to 76%) shows they had a survival and reproductive advantage. The change occurred because after the environment (maybe more human - weeding activity) changed, farmers (a selective pressure) were more likely to remove drooping - leafed barnyard grass.

Answer:

The percentage of grass plants with upright leaves increased in the population. This suggests that grass plants with upright leaves were more likely to survive and reproduce than grass plants with drooping leaves. The change occurred because there were more farmers weeding the rice fields by hand after the population's environment changed. So grass plants with drooping leaves were more likely to be removed by farmers.