Questions: Many human traits, such as our performance on intelligence tests or our susceptibility to heart disease, are . determined by genes in some people and by the environment in other people determined solely by environmental factors influenced by both genes and the environment determined only by our genes

The answer is the third one: influenced by both genes and the environment.

Explanation for each option:

1. Determined by genes in some people and by the environment in other people: This option suggests a mutually exclusive influence of genes or environment, which is not accurate for most human traits. Traits are typically influenced by a combination of both genetic and environmental factors in all individuals, not just one or the other.

2. Determined solely by environmental factors: While the environment plays a significant role in shaping many traits, it is rarely the sole determinant. Most traits result from the interaction between genetic predispositions and environmental influences.

3. Influenced by both genes and the environment: This is the correct answer. Most human traits, including intelligence and susceptibility to diseases, are the result of complex interactions between genetic factors and environmental conditions. This concept is known as gene-environment interaction.

4. Determined only by our genes: Although genes play a crucial role in determining many traits, they are not the only factor. Environmental influences can significantly modify or influence the expression of genetic traits.

In summary, human traits are typically influenced by a combination of genetic and environmental factors.