Ken enjoys bird watching. every summer, he sees many ruby-throated hummingbirds in his garden. however, during the winter, he never sees any ruby-throated hummingbirds. which of the following is a testable hypothesis that ken could make to explain the winter absence of the hummingbirds?

How does the molecular clock work? a. it analyzes the brain functionality of two different species.b. it examines and compares the physical characteristics of two different species.c. it illustrates relationships between two different species.d. it compares the number of mutations that exist in the dna of two different species.

What is the process of pulling apart an n2 molecule nevermind i got it

The ancestors of plants that lived in water had plenty of water for the young. angiosperms are a group of land plants that evolved a reproductive trait for living on land. this trait protect young plants by allowing them to grow only when water is present and the conditions for healthy development are right. what trait most likely young angiosperms in this way?