Step-by-step explanation:
1) 72 of their chromosomes would be somatic and only 2 would be gametes. the number is always two as (normally) an organism will have either 2 X chromosomes (female) or an X and Y chromosome (male).
2) without genetic diversity, an entire species of an organism can go extinct from the same thing as none of them would have mutated any defenses and pass them off to their offspring.
hope this helps :)