As shown in the figure above, twenty fruit flies are placed in each of four glass tubes. The tubes are sealed Tubes I and II are partially covered with black paper, Tubes III and IV are not covered. The tubes are placed as shownThen they are exposed to red light for five minutesThe number of flies in the uncovered part of each tube is shown in the drawing

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.