21&22

QUESTION 21 A physical, chemical, or biological agent that causes cancer is called a(n) D a. oncogene. Ob. carcinogen. c. regulatory protein. Od. virus QUESTION 22 3 The illustration below shows the developmental sequence leading to an adult human. Every step, except one, requires that mitosis occur; the one exception is Adult Egg (n) ZygoteMrulalastocyst (2n) a. zygote to morula. b. egg and sperm to zygote. c. blastocyst to embryo. d. fetus to adult. Save and Submit to sque and submit. Click Save All Answers to save all answers Save All Answers