Into how many classes are the angiosperms (flowering plants) classified?

Which of the following key factors makes a plasmid a suitable vector in genetic engineering?

If the displacement $(x)$ and velocity $(v)$ of a particle executing simple harmonic motion are related through the expression $4 v^2 = 25 - x^2$,then the time period is

In a $500 \ mL$ capacity vessel,$CO$ and $Cl_2$ are mixed to form $COCl_2$. At equilibrium,it contains $0.2 \ mole$ of $COCl_2$ and $0.1 \ mole$ of each of $CO$ and $Cl_2$. The equilibrium constant $K_c$ for the reaction,$CO(g) + Cl_2(g) \rightleftharpoons COCl_2(g)$ is:

The wavelengths of two notes in air are $\frac{36}{195} ~m$ and $\frac{36}{193} ~m$. Each note produces $10$ beats per second separately with a third note of fixed frequency. The velocity of sound in air in $m/s$ is

Two objects of masses $200 \text{ g}$ and $500 \text{ g}$ possess velocities $10 \hat{i} \text{ m/s}$ and $(3 \hat{i} + 5 \hat{j}) \text{ m/s}$ respectively. The velocity of their centre of mass in $\text{m/s}$ is: