Which of the following is not included in the five-kingdom classification system?

The magnetic susceptibility of the material of a rod is $499$. Permeability of vacuum is $4 \pi \times 10^{-7} \ H/m$. Absolute permeability of the material of the rod in $H/m$ is:

In a haplontic life cycle,how many of the four haploid nuclei degenerate?

Ectophloic siphonostele is found in ...........

The covalent alkaline earth metal halide $(X = Cl, Br, I)$ is

The diameter of a plano-convex lens is $6 \ cm$ and its thickness at the center is $3 \ mm$. If the speed of light in the material of the lens is $2 \times 10^8 \ m/s$,the focal length of the lens is.......$cm$.