All of the following are excretory organs except the
a. skin.
b. lungs.
c. heart.
d. kidneys.

Which best describes red blood cells? a. they are colorless b. they protect against disease-carrying microorganisms c. they transport oxygen throughout the body d. they aid in blood clotting

Imagine ? person stepping on a pin and pulling his or her foot way look at the réfléchir arc of the scenarios below

Which of the following is not a defining characteristic of plants?