The Law of Dominance says that when an organism is heterozygous for a trait, only the dominant allele will produce a phenotype.
The answer to this question would be: vitamin
Some bacteria can produce vitamin K2 in the intestine. Other bacteria also able to change vitamin K1 into vitamin K2. But the amount produced is not much, so human still need to fulfill it from the diet. Vitamin K has a role in calcium regulation and in blood clotting pathway.
Stomata play an important role in photosynthesis as they allow the plant to absorb carbon dioxide from the environment. In exchange, stomata allow oxygen, which is a waste product of photosynthesis, to be released. In the process, water vapor is also lost as the internal parts of the leaves are exposed. To reduce exposure, stomata are found on the underside of the leaves. They are protected from the sun as excessive heat can increase the rate of water vapor leaving and thus wither the plant. Stomata also have guard cells around the epidermis that close when too much water is being lost.