Studies reveal that ventilation drifts upward during constant-load submaximal exercise performed in a hot and humid environment. this is likely due to

The answer would be; a significant increase in blood temperature.

The muscle contraction from exercise will produce heat that will increase the body temperature. In a hot and humid condition, this will make the body temperature hard to be lowered. The increase of blood temperature will influence the respiratory control center, makes the respiration drift upward.

The answer would be sand and gravel

Ibelieve the answer is c.