Which of the following is the most important cause driving animals and plants to extinction?

The ratio of the magnetic field at the centre of a current-carrying circular coil to its magnetic moment is $x$. If the current and the radius are both doubled,the new ratio will become:

The solution of $x \frac{dy}{dx} = y + x e^{y/x}$ with $y(1) = 0$ is

Which of the following hormone levels causes the release of an ovum from the Graafian follicle (ovulation)?

An ideal refrigerator has a freezer at a temperature of $-13^{\circ}C$. The coefficient of performance of the refrigerator is $5$. The temperature of the air (to which heat is rejected) will be:

The Test-tube Baby Programme employs which one of the following techniques?