Which photosynthetic pigments are present in algae?

If $P_1$ and $P_2$ are two points on the ellipse $\frac{x^2}{4} + y^2 = 1$ such that the tangents at these points are parallel to the chord joining the points $(0, 1)$ and $(2, 0)$,then the distance between $P_1$ and $P_2$ is:

If $\overline{a}=\frac{1}{\sqrt{10}}(3 \hat{i}+\hat{k})$ and $\overline{b}=\frac{1}{7}(2 \hat{i}+3 \hat{j}-6 \hat{k})$,then the value of $(2 \overline{a}-\overline{b}) \cdot [(\overline{a} \times \overline{b}) \times (\overline{a}+2 \overline{b})]$ is

The least positive integer $n$ for which $(1+i)^n=(1-i)^n$ is

$A$ pair of insectivorous plants is

The sum of the spin only magnetic moment values $(in \ B.M.)$ of $\left[ Mn ( Br )_6\right]^{3-}$ and $\left[ Mn ( CN )_6\right]^{3-}$ is $....$ .