Which of the following types of mutation would convert a proto-oncogene into an oncogene?
a. a deletion of most of the proto-oncogene coding sequence
b. a mutation that blocks transcription of the proto-oncogene
c. a mutation that creates an unstable proto-oncogene mrna
d. a mutation that greatly increases the amount of the proto-oncogene protein

false because ozone (o3) depletion does not cause global warming, but both of these environmental problems have a common cause: human activities that release pollutants into the atmosphere altering it.

global warming is caused primarily by putting too much carbon dioxide into the atmosphere when coal, oil, and natural gas are burned to generate electricity or to run our cars.

explanation:

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.