Why don't we have the same antibody for the same antigen?

Complete the following statements about the functions of the digestive system.carbohydrates and fats are digested in secretes enzymes that aid in the digestion of carbohydrates, fats, and proteins.the secretes bile; bile is stored in undigested food is processed into feces in feces is then stored in until it is eliminated from the body via

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.

Me with these questions image attached