Due to collisions between particles in the spinning cloud, the solar nebula begins to flatten. The particles in the gas cloud first have all different speeds in different directions. As they start colliding with each other, their final velocity is the average of the two initial velocities before collision.
A single molecule is the one that is responsible for initiating a signal transduction pathway. The answer in this question is a single molecule. Molecule is defined as an electrically neutral group of two atoms or more held together by a chemical bonds.
The answer is B.
Im pretty sure water is important for some organisms.
