Final answer:
The correct answer is b) Environmental influence, as it explains the wider variation in Tanya's weight. Tanya's genes have a broader range of reaction to environmental factors such as physical activity and diet, compared to Jade.
Step-by-step explanation:
The student's question pertains to the concept of the interaction between genes and environment in determining an individual's weight. The question is: 'There appears to be a wider _____ for Tanya's genes that help determine weight.'
The correct answer is b) Environmental influence.
The explanation involves understanding that while genetics play a crucial part in determining traits like body weight, environmental factors can significantly affect how these genes are expressed. For example, the amount of physical activity, diet, socioeconomic status, and other environmental factors can influence an individual's weight. Since Tanya's weight fluctuates depending on how active she is, her genotype for weight has a wider range of reaction to environmental influences compared to Jade, who remains about the same weight regardless of lifestyle changes.
In summary, the wider variation in Tanya's weight suggests a more significant environmental influence on her genetic potential for weight than Jade experiences.