Secondary productivity is the rate of formation of new organic matter by:

The heat energy absorbed by a system undergoing the cyclic process shown in the figure is:

$A$ clock $S$ is based on the oscillation of a spring,and a clock $P$ is based on pendulum motion. Both clocks run at the same rate on Earth. On a planet having the same density as Earth but twice the radius,which of the following is true?

Which of the following is a major source of protein?

The contrapositive of the statement 'If two numbers are not equal,then their squares are not equal' is:

In the expansion of $(1+x)^n$,the coefficients of the $p^{th}$ and $(p+1)^{th}$ terms are respectively $p$ and $q$. Then $p+q$ is equal to: