Which kingdom consists of organisms that are multicellular,aquatic or terrestrial,heterotrophic,and eukaryotic?

The wavelengths of electron waves in two orbits is $3: 5$. The ratio of kinetic energy of electrons will be

In a series of $2n$ observations,half of the observations are equal to $a$ and the remaining are equal to $-a$. If the standard deviation of the observations is $2$,then what is the value of $|a|$?

Let $A$ and $B$ be independent events with $P(A)=0.3$ and $P(B)=0.4$. Find $P(A | B)$.

The minimum value of $|z-1|+|z-5|$ is

Two blocks $A$ and $B$ of masses $1\,kg$ and $2\,kg$ are connected together by a spring and are resting on a horizontal surface. The blocks are pulled apart so as to stretch the spring and then released. The ratio of $K.E.s$ of both the blocks is