which is a result of a seasonal change ( meaning a change that happens over and over at a certains time of year)?

The frogs digging into mud to hibernate in winters. This is a result of seasonal change in which the cold blooded animals go into hibernation during winters as they cannot maintain their body temperature with respect to the changing environment.

Explanation:

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.