Solution exposure to air and light with the manual processing technique can be avoided by using a:

a. thermometer
b. tank cover
c. timer
d. stirring rod

Answer is B. Tank cover.

Explanation:

A tank can be described as a container,usually large, but sometimes small, which is used to house gases and liquids.

A cover , which can also be referred to as a lid, serves a  role as a closure or seal.

The use of a tank cover will prevent the solution from being exposed to air or light.

answer by yourhope:

answer is

human impact on the environment can be seen in the deterioration of the !

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