What is the main toxic waste that the kidneys filter from the blood?

Two green plants are kept separately in oxygen-free containers,one in the dark and the other in continuous light. Which one will live longer? Give reasons.

What is the significance of emulsification of fats?

Which is the internal energy reserve in plants? Do the animals have the same energy reserve?

$(a)$ Name the following:
$(i)$ Part in which urine is produced.
$(ii)$ Part which stores the urine.
$(iii)$ Part which connects $(i)$ and $(ii)$.
$(iv)$ Part from which urine is passed out.
$(b)$ Name the factors on which the amount of water reabsorbed along the tubular part of the nephron depends.

Explain the role of the mouth in the digestion of food.