Organisms that spend their entire adult lives attached to one spot are said to be
a. sessile.
b. heterotrophic.
c. flagellated.
d. symmetric.

in an echinoderm, the structure that operates like a living suction cup is the
a. madreporite.
b. tube foot.
c. stomach.
d. water vascular system.

Mg is used to measure mass

Cis the

Mars and earth have quite a few things in common. both are  terrestrial planets, both are located within the sun’s  habitable zone, both have  polar ice caps, similarly  tilted axes, and similar  variations in temperature. and according to some of the latest scientific data obtained by rovers and atmospheric probes, it is now known that mars once had a  dense atmosphere  and was covered with  warm, flowing water.