Animals need various nutrients in order to live and grow nitrogen for example is a nutrient that is needed to form molecules such as DNA and Arnie how do animals obtain nitrogen

Cell division is important to single celled organisms because it allows the cells to reproduce. through cell division, cells make exact copies of themselves. when single celled organisms go through cell division, they make exact copies of themselves which is how they reproduce.

Molecules called lipids have long hydrocarbon chains that determine the way they act. they can be fats, oils, or hormones, and even exist in our cell membranes 

Synapse nervous system they process and transmit signals. in a neuron