Sea urchins are preyed about by many predators that inhabit their marine environment, but also those animals that don't. The main predators of the sea urchin are crabs, large fish, sea otters, eels, birds and humans.
Interphase is the phase during which the growth of the cells take place along with the metabolic activity but the nuclear division in the cell does not occur. The three stages included within the interphase are the G1, S and G2.
The cytoplasm of bacterial cells consists consists of an aqueous solution of three groups of molecules: macromolecules such as proteins (enzymes), mRNA and tRNA; small molecules that are energy sources, precursors of macromolecules, metabolites or vitamins; and various inorganic ions and cofactors (see Tables 9, 10,11).