Proto-oncogenes can change into oncogenes that cause cancer. which of the following best explains the presence of these potential time bombs in eukaryotic cells?
a. proto-oncogenes first arose from viral infections.
b. proto-oncogenes are mutant versions of normal genes.
c. proto-oncogenes are genetic "junk."
d. proto-oncogenes normally regulate cell division.

The correct answer is D.

Explanation:

Proto-oncogenes code for proteins that usually help to regulate cell growth and differentiation.

If they acquire a mutation, they become oncogenes and therefore can induce cancer.

Additionally, if they increase the amount of certain proteins concentration or acquire chromosomal translocations they can also become oncogenes.

answer:   option a) glucagon was secreted by his pancreas before he ate the cookies because blood glucose was low. insulin was secreted after he ate the cookies because his blood glucose was high.

explanation:

i think its through the fallopian tube