Name the organisms which utilize complex substances and break them down to simpler forms.

Why do fishes die when taken out of water?

$(a)$ Draw a diagram of the human urinary system and label the following parts:
$(i)$ Kidney
$(ii)$ Ureter
$(iii)$ Urinary bladder
$(iv)$ Urethra
$(b)$ Name the two major components of normal human urine.

Liver is the largest organ as well as the largest gland of the body.

In which of the following vertebrate group/groups,heart does not pump oxygenated blood to different parts of the body?

During deficiency of oxygen in tissues of human beings,pyruvic acid is converted into lactic acid in the