Water is stored mainly in the central vacoule of a plant cell.
Protects the growing tip of the plant
D. Gravity and Distance. The distance earth is from the sun is what's keeping us from barreling into the mass of flame and heat. The distance between us and the moon is what keeps the moon from crashing into us. It could not be C, as the definition of inertia is: "a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force." Hope this helps :)
The way that you could use molecular biology to determine whether these birds have evolved from a shared common ancestor is to take a look at their proteins, RNA, and DNA. Because the more similar these things are in the two types of birds, the more possible it is that they are somewhat connected via a common ancestor.