C. the answer is c. i just took this test on keystone (i think this is keystone question. right?0
Answer:
Actually the economy today of the USA is very good compared 50 years ago.
Explanation:
Answer:
A.
Explanation:
Cell size is limited by a cell's surface area to volume ratio. A smaller cell is more effective and transporting materials, including waste products, than a larger cell. Cells come in many different shapes.
Answer:
Explanation:
Increased heart rate
Increase convertion and delivery of oxygen are some short term effects of exercise on the cardiovascular system