In the 1600 what scientist discovered microbes in the pond by using a microscope

The body is protected against harmful flu viruses by

Epinephrine is a hormone released from the adrenal gland of the body, most often in a stressful situation. it is known as the "fight-or-flight" hormone. one way that it causes a response in the body is to activate receptors on muscle cells. where are these cellular receptors located? a. on the cell membrane b. in the nucleus c. on the cell wall d. around the mitochondria

Does the sun release radiant energy?