Answer: Option '4' is correct.
Step-by-step explanation:
An increase in the number of frogs is likely possible when there is decrease in the number of trees.
As we know that Frogs are amphibians which means they live both on land and water.
But they do not live on trees.
If there is decrease in the number of trees then frogs get more space on land to reproduce more.
Hence, the number of frogs will get increase with decrease in the number of trees.
Thus, Option '4' is correct.