The function of muscular contractions that force water into the tube feet is
a. regeneration.
b. allowing the echinoderm to float with ocean currents.
c. digestion.
d. to enable the echinoderm to attach to surfaces.

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

protist eukaryotes that are not plants, animals, or fungi ("misfits")