Hi,
I think that you're missing some options, but here they are (let me know if I'm right!
-A population of wolves was introduced
-The amount of disease in the deer population decreased
-More grass was planted
Now, if the gene diversity decreased, it means that a lot of deer died. This could happen because wolves were introduced -this is the correct answer, and the wolves ate some deer.
Answer:
Organism
Explanation:
The other options are all smaller than an organ system.
A cell is the smallest. Many cells make a tissue, many tissues form an organ and many organs form an organ system. Many organ systems form the organism :))
Selectively permeable means that it allows only the nutrients it needs but keeps out the bad things out. For example, some windows have the netting to keep out the bugs from going into your house. That is selectively permeable.