During strenuous exercise, glucose is converted into
a. Glycogen
b. Pyruvic acid
c. Starch
d. Lactic acid

Hint: Strenuous exercise being able to faster the breath during the high activities. Energy production is faster than the rate in which the human body delivers oxygen during this time. Anaerobically energy generated during the muscles exercise. For the continuous energy production during this stage the body converts pyruvate obtained from glucose into the lactic acid to generate a continued amount of energy when the limited oxygen is present in it.

Complete answer:
Physical exercise that helps to increase and maintain overall health, wellness and physical fitness. These include strengthening the muscles, cardiovascular, weight loss and maintenance and for enjoyment and honing athletic skills.

Regular aerobic exercise has been helped to prevent the serious life threatening disease such as high blood pressure, heart disease, insomnia, depression and type 2 diabetes.

Lactate is converted form of the pyruvate into the muscles cells and by accepting the electron from NADH, which oxidizes NADH back to NAD+ to allow glycolysis in the pyruvate that is reduced to lactic acid under the anaerobic conditions.

Lactate produced by anaerobic glycolysis in the muscles that move to the liver and converted to glucose and then return back to the muscles and metabolic pathway known as the name Cori cycle. Cori cycle introduced by Carl Ferdinand Cori and Gerty Cori.

Hence, the correct answer is option (D).

Note: During the cycling on hills swimming laps, racquetball, jogging, basketball and aerobics are the type of strenuous activities. Strenuous exercise improves heart health, boosts metabolism and increases the production rate of the calories and is also known as the name high intensity exercise.