Which is a leading theory for the formation of fossil fuels?

a. fossil fuels arrived on earth from comets and asteroids.

b. carbon dioxide levels decreased, resulting in nitrogen fixation.

c. earth cooled, changing oxygen into carbon.

d. fossil fuels are the remnants of organisms that lived a long time
ago and were buried, heated, and formed into hydrocarbons.

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

Mineral rich water heated by newly found oceanic crust escapes through cracks in the ocean floor called

9. the history of life on earth is recorded in