An average person (let's say one that weights 70 kg) has about 5.5 liters of blood (that's a little more than 160 ounces or 1.2 to 1.5 gallons). Other way of saying this is : about 7% of body weight.
The primary energy system to fuel cycling for 15 minutes is THE AEROBIC GLYCOLYSIS SYSTEM.
There are different energy systems for fueling different types of physical exercise, the type of system that is used depend on the duration of the physical exercise. The energy system that exist are anaerobic glycolysis, aerobic glycolysis, phosphagem system and fatty acid oxidation. The aerobic glycolysis energy system relies on the complete breakdown of glucose. The pyruvate which is the end product of glucose oxidation is further broken down to acetyl coA, which then enters into the citric acid cycle. The aerobic glycolysis energy system is used for physical exercises that last between three to twenty minutes.
Answer:
B- environmental factors do most of the “selecting.”
Explanation:
Natural selection is the environment that the organism lives in, and the process which that organism changes by.
Artificial selection is when humans intervene and create an organism that isn't suited for their specific environment, but rather for the humans own liking.
Think of breeding dogs to be smaller, or more fluffy and adorable. These are not traits to help them survive in where they original environment was.