Coral reefs:

(A) may occur as barrier, fringing, or atoll formations.
(B) protect coastlines from erosion.
(C) are found in shallow, nutrient poor, tropical waters.
(D) are the most diverse of all marine environments.
(E) All of these choices are correct

What is a gene ? a) a section of a protein that codes for dna. b) the alternate version of a trait. c) the visible trait in the f1 generation. d) a section of dna that codes for a specific trait .

Awoman whose sister tested positive for a specific mutation in the brca1 gene, which increases the risk for breast and ovarian cancer, is found not to have that mutation but does have a mutation of unknown significance near the known mutation site. how should this woman be counseled? select one: a. she should be informed that her risk for breast cancer is greater than the general population but not as great as her sister’s risk. b. she should be informed that because she does not have the mutation, her risk for breast cancer is not greater than that of the general population. c. she should be informed of her gene mutation status and be presented with all the available prophylaxis options and reconstruction options. d. she should be informed that she does not have the specific mutation but that because another mutation is present she should be vigilant about screening

Ihave no idea how to solve these. plus there's another question that is 2) a 10 kilogram meteorite is collected in space and brought back to earth. it is composed of 1.25 kg of uranium-238 and 8.75 kg of lead-206. how many u-238 half lives have passed? what is the approximate age of the meteorite?