A reflex, or reflex action, is an involuntary and nearly instantaneous movement in response to a stimulus. ... The reflex is then an automatic response to a stimulus that does not receive or need conscious thought.
Nonrenewable resources are used commonly and are quickly running out, and it takes longer for us to form more of these.
A target cell respond to a hormone because it bears receptors
The process in which the environment<span> selects </span>organisms<span> that will survive is called natural selection. It starts with overproduction; when an </span>organism<span> produces more offpsrings than can survive. The second is variation. Because there are so many offsprings, there will be variations.</span>