Boron in green plants assists in

If $\cos (x-y), \cos x, \cos (x+y)$ are three distinct numbers which are in harmonic progression and $\cos x \neq \cos y$,then $1+\cos y$ is equal to

In the given circuit,find the equivalent resistance between points $a$ and the combination of $b$ and $c$ (where $b$ and $c$ are connected together).

Which of the following is the richest source of plant protein?

Archaea that live in hot springs belong to which group?

The catalyst and promoter respectively used in the Haber's process of industrial synthesis of ammonia are