How does helium differ from the elements in its group?

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

People with one sickle cell allele are not likely to get malaria. what is this an example of?

Water diffusing through a semipermeable membrane is called