What usually causes some species to become extinct?

Amutagen is 1: a living thing that has undergone a mutation. 2: an agent that causes a mutation in dna. 3: a mutation that has affected one gene. 4: a chemical that can poison living cells.

Which two criteria must be met before scientist can use radiocarbon dating? explain your answer

14. which of the following codons code for threonine? a. ucg b. ugu c. cga d. aca