Which of the following observations would support the claim that a particular mutation is neutral?
a
The frequency of the mutation in a population, once it first appears, tends to increase over time.
b
In a given population, individuals that possess this mutation have a greater rate of reproduction.
c
The mutation is higher in populations of organisms that produce fewer offspring and have shorter life spans.
d
The frequency of the mutation goes up and down with no observable effect on the health of a population.