Answer: Cell
Explanation:
The cell is the structural and functional unit of life. It is the the most basic level. A life starts from a single cell.
When a male and female gamete(germ cell) fuse together they form zygote. Firstly it is a single cell surviving inside the mother's womb.
Then differentiation takes place and the cell keeps on dividing to form different tissue layers and then organs form which makes a complete baby. Hence, zygote and germ cell are cellular level of organization.
The key effect that results in the stimulation of eating is to activate NPY neurons within the hypothalamus. Infusion of ghrelin stimulates food intake in the brain. NPY or Neuropeptide Y acts as a neurotransmitter and NPY stimulates human from eating.
<span>Isometric muscular contractions do not change the length of the muscle they are responsible for movement. Isotonic muscular contractions will lengthen or shorten the muscle. Concentric contractions shorten the muscle. Eccentric contractions lengthen the muscle.</span>
The first one is evaporation, condensation, precipitation, and collection. (Hope it helped)