The solution of $x dx + y dy = x^2 y dy - x y^2 dx$ is

Choanocytes are present in

If both the mass and the radius of the earth decrease by $1\%$,the value of the acceleration due to gravity will

$A$ black body of mass $34.38 \ g$ and surface area $19.2 \ cm^2$ is at an initial temperature of $400 \ K$. It is allowed to cool inside an evacuated enclosure kept at a constant temperature of $300 \ K$. The rate of cooling is $0.04 \ ^{\circ}C/s$. The specific heat of the body in $J \ kg^{-1} \ K^{-1}$ is (Stefan's constant $\sigma = 5.73 \times 10^{-8} \ W \ m^{-2} \ K^{-4}$)

Water-containing cavities in vascular bundles are found in:

$2 \tanh^{-1} \frac{1}{2}$ is equal to