The sliding filament theory explains how these cross-bridges are formed and the subsequent contraction of muscle. The Sliding Filament Theory For a contraction to occur there must first be a stimulation of the muscle in the form of an impulse (action potential) from a motor neuron (nerve that connects to muscle).
A plant scientist is a biologist who focuses on various types of plants, usually those grown as crops for food, fiber, and other purposes. This work can involve field and lab work on a variety of topics, from improving yields to developing more nutritious food plants for the purpose of fighting hunger in underdeveloped nations.
Scientist is a position as much as a credential. NdGT has every right, by virtue of his PhD, to continue to be addressed as Dr. Tyson.. But I still don't think that makes him a scientist. A retired MD might still be a doctor, but I'm not convinced they're still a physician.