Which of the following is not a waste that is removed from the body through excretion?
a. blood
c. carbon dioxide
b. salt
d. urea

The correct answer is a - blood.

Blood is a tissue. It is   kind of connective tissue composed  of an aqueous fluid called plasma  in which are suspended three components namely red blood cells, white blood cells, and platelets.

Two main functions of blood is transport of  substances to and from each cell in the body, and  to provide immunity and protection against invading pathogens.

It is therefore not a waste product but  it carries waste products such as carbon dioxide to the lungs to be expelled.

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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