How can a population grow? Ecology

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?

If you relate the doppler effect on sound to the color of light waves, a police car would be the color as it approaches and the color as it recedes away from the observer.

Mutations can be categorized based on the kind of effect they have on an organism