Many of the body's biological processes operate without conscious control because of the:

Answer;

-Autonomic nervous system

Explanation;

-The autonomic nervous system regulates a variety of body process that take place without conscious effort. The autonomic system is the part of the peripheral nervous system that is responsible, as the name implies, for regulating involuntary body functions such as heartbeat, blood flow, breathing, and digestion.

-It also controls some of the muscles within the body. We are often unaware of the ANS because it functions involuntary and reflexively. For example, we do not notice when blood vessels change size or when our heart beats faster.

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)