Earthworms are ........

$3.011 \times 10^{22}$ atoms of an element weigh $1.15 \ g$. The atomic mass of the element is

Which of the following is not correct?

How many chloride ions are there around a sodium ion in a sodium chloride crystal?

$A$ stone is dropped in a quiet lake and it is observed that waves move in circles. If the radius of a circular wave increases at the rate of $2 \text{ cm/sec}$,then the rate of increase in its area at the instant when its radius is $10 \text{ cm}$,is (in $\text{cm}^2/\text{sec}$): (in $\pi$)

The branch of botany that deals with the study of algae is known as: