The proper function of the stomates on the leaf (and therefore, the function of water and CO2 movement) is influenced most by which element

Sunlight.

Explanation:

Sunlight is responsible for proper functioning of stomata present on the leaves because the stomata only opens when there is sunlight and when the stomata opens, carbondioxide gas is absorbed by the leaves from the air while the water is taken from the roots which combines together to form glucose and oxygen. Glucose is stored in different parts of the plant while some oxygen is used by the plants in the process of respiration while the remaining oxygen is released in the atmosphere through stomata.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.