According to the Neo-Darwinian theory,which of the following is responsible for the origin of new species?

In the circuit shown below,the ammeter reading is zero. Then the value of the resistance $R$ is (in $\Omega$)

$A$ stick of length $L$ and mass $M$ lies on a frictionless horizontal surface on which it is free to move in any way. $A$ ball of mass $m$ moving with speed $v$ collides elastically with the stick at its end,as shown in the figure. If after the collision the ball comes to rest,then what should be the mass of the ball?

$A$ circular disc is rolling on a horizontal plane. Its total kinetic energy is $300\,J$. What is its translational kinetic energy in $J$?

Which parasite stage breaks down hemoglobin with the help of enzymes?

If $y = (\cos x^2)^2$,then $\frac{dy}{dx}$ is equal to: