The correlated trait exercise shows that :
a) when two characters are correlated, selection always favors larger values of both or smaller values of both
b) when two characters are correlated, one of them can evolve toward higher values even if smaller values are better for survival
c) when two characters are correlated, selection is always strong on both or weak on both
d) when two characters are correlated, the optimal values and selection strengths rise and fall together

The correlated trait exercise shows that when two characters are correlated, the optimal values and selection strengths rise and fall together.

Explanation: Correlation refers to statistical (linear) relationship between two random variables. When traits are correlated, change in one is associated with change in the other.

Correlation coefficient (c.c.) measures strength of association between two variables in the same individual or experiment. It can range from -1 to +1. C.c. can be positive, negative or weak.

1. A positive c.c. means that an increase in one variable is associated with an increase in the other variable.

2. A negative c.c. means that an increase in one variable is associated with a decrease in the other.

3. A c.c. near zero indicates a weak relationship between the variables.

Correlation can be represented by scatter plot as shown in the attached image.

the correct option is option d

"d.) carbon dioxide and hydrogen sulfide"