$........$ is the unit of heredity.

On which of the following plant species has Mendel worked?

Which radioactive element (isotope) is used to determine the age of fossils?

It is a commonly held misconception that the mother's egg is responsible for determining whether the baby will be a boy or a girl. But actually,it is the father's sperm that decides this. Which of the following makes the sperm the decisive factor?

What is the scientific name of the human species?

$(a)$ What function is performed by human arms,forelimbs of a dog,and forelimbs of whales?
$(b)$ Which type of organs are these?
$(c)$ Why are they called so?