Which of these events is an example of a secondary disturbance in an
ecosystem?

A secondary ecological disturbance will be the one which will indirectly affect the ecosystem

The forest fire is the example of secondary disturbance because of the fact that initially the forest will affect a small region or small number of tree species but may spread to the large region.

Explanation:

I majored in Biology

lysosome is this part of the cell is surrounded by a very thick outer membrane to protect the rest of the cell from its strong enzymes.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).