Part 3
1. what is the contour interval?
2. what are the elevations of lines a and b?
3. provide an approximate elevation for points w (point is inside the circle), x, and y (point is on the line).

a sperm cell fertilizes an egg cell.

the electromagnetic energy from the sun arrives in the form of visible and invisible light.

those characteristics are cellular organization, reproduction, metabolism, homeostasis, heredity, response to stimuli, growth and development, and adaptation through evolution. some things, such as a virus, demonstrate only a few of these characteristics and are, therefore, not alive