Order of toxicity among ammonia,urea and uric acid (from lower to higher) is

The variance of the first $50$ even natural numbers is

$A$ conducting wire frame is placed in a magnetic field which is directed into the paper. The magnetic field is increasing at a constant rate. The directions of induced current in wires $AB$ and $CD$ are

If the vectors $\hat{i}+3 \hat{j}+4 \hat{k}$ and $\lambda \hat{i}-4 \hat{j}+\hat{k}$ are orthogonal to each other, then $\lambda$ is equal to:

The blood leaving the liver and moving towards the heart has a higher concentration of which of the following?

If $|a| = 2$,$|b| = 3$ and $a, b$ are mutually perpendicular,then the area of the triangle whose vertices are $0, a + b, a - b$ is