When parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus. The distance between the principal focus and the centre of the lens is called the focal length.
Emperor penguins need lungs to breathe. In penguin lungs, air never stops. ... Once the air goes farther into the trachea it splits into two different directions into both lungs. To get the oxygen into the blood cells, it must come "within small distance of the penguin blood cells".
Malignant tumors are classified according to the type of cells that give rise to them.
Answer:
viruses, bacteria, fungi, and parasites
Explanation: