Which environmental factor could lead to a decrease in genetic variation in a population of tuna? an increase in food availability
an increase in pollution
a decrease in tuna fishing
a decrease in tuna predators

The environmental factor that could lead to a decrease in genetic variation in a tuna population is an increase in pollution (second option).

Explanation:

There is a correlation between genetic variability and environmental pollution, the latter being a factor that impacts negatively on the variability of a specific population.

The concept of pollution stress not only implies a low rate of reproduction, but it is also a factor that prevents genetic exchange with other populations, which is a factor that makes the genetic variability decrease in a population.

For these reasons an increase in pollution implies a decrease in genetic variability in a tuna population.

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