How can a person donate blood and never run out of it?
a. blood components are continuously pumped by the heart.
b. blood components are continuously circulated through the blood vessels.
c. blood components are continuously produced in the bone marrow.
d. blood components are continuously digested by enzymes.

The correct answer is- C. Blood components are continuously produced in the bone marrow.

Formation of blood cells is a continuous process that occurs in the bone marrow ( a gelatinous, soft tissue present within bones) of adults.

This process is called as hematopoiesis, in which undifferentiated precursor cells ( also called stem cells) are developed and differentiated into particular blood cell type ( having specific function).

Thus, through this continuous process, all the components of blood can be replenished whenever they are required.

Therefore, when a person donates blood, he never run out of it.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.