How does a healthy environment help in maintaining happy and prosperous life in long type

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.

Adigestive system that is a series of tubes beginning at the mouth and ending at the anus is a digestive system.

Sea stars, sea urchins, sand dollars, and brittle stars are all memeber of a group, what is the common name of the group they are all in