<span>The fourth level of cell organization is the
organ level. The organ level is a structure composed of collections of tissues
that perform specific functions in a living organism. Organs that are found in
a human body are the heart, lungs, brain, pancreas, liver, among others. These
organs perform specific functions and work in an interconnected manner for the
human body to function well. When organs work together, they are called organ
systems which are already the fifth level of cell organization.</span>
It's called major histocompatibility complex protein
Answer:
ATP can be used to store energy for future reactions or be withdrawn to pay for reactions when energy is required by the cell. Animals store the energy obtained from the breakdown of food as ATP. Likewise, plants capture and store the energy they derive from light during photosynthesis in ATP molecules.
The homology of animals is based on scientists current understanding on the evolutionary history of living species.
