Insulin. Insulin is a hormone made by the beta cells in the pancreas. It is the key that opens the doors of cells and allows glucose to get into the cell. Each cell needs glucose to function. Carbohydrates in food are broken down into glucose which enters the blood stream.
The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants.
In the Hipparchian and Ptolemaic systems of astronomy, the epicycle was a geometric model used to explain the variations in speed and direction of the apparent motion of the Moon, Sun, and planets. In particular it explained the apparent retrograde motion of the five planets known at the time. Secondarily, it also explained changes in the apparent distances of the planets from the Earth. It was first proposed by Apollonius of Perga at the end of the 3rd century BC. It was developed by Apollonius