Some activities that cell requires energy may include cell division, active transport, protein synthesis etc.
In human, Cells get their energy by the food we eat. The nutrients in the food breaks down into soluble and simple molecules in stomach and small intestine and it is absorbed through the small intestine and assimilated into the cells, becoming part of it, providing the uses for each type of nutrient. And of course, many of them is the energy source.
Do you have a conversion sheet? If not, go ahead an google one and reply to this comment so I can teach you how to convert quarts into liters step by step.
Ultraviolet radiation is the primary cause of sunburns
How would removing your umbrella in a rainstorm affect your ability to stay dry? The definition of a keystone species is a species that has a crucial role in an ecosystem. Removing one gear from a clock would stop the clock from working. Removing/changing a major contributer to a balance and natural ecosystem can potentially collapse the entire system altogether.
