The gravitational attraction between two objects is determined by the mass of two objects and the

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.

Nucleic acid certain protein cell membranes certain carbohydrates

The response is the basis for vaccination. primary secondary tertiary none of the above