The answer is A. Gravity pulls down on all parts of a plant.
Often these molecules are carbohydrates, attached to certain lipids, or also I believe are called as glycolipids. These are marker molecules and are used to distinguish cells from each other. As cells can differentiate from one another based on the composition of the carbohydrates present on the lipids, I believe.
When there are two recessive parents, that means the recessive trait will go into the child. Hope this helps.
