It provides precursor for the synthesis of stress hormone in plants.

It protects chlorophyll $a$ from photo-oxidation.

It is an accessory pigment which absorbs light at $600-700 \mathrm{~nm}$.

It accumulates in chromoplasts during fruit ripening.

Experiment $2<$ Experiment $1<$ Experiment 3

Experiment $1<$ Experiment $2<$ Experiment 3

Experiment $1=$ Experiment $2=$ Experiment 3

Experiment $2<$ Experiment $1=$ Experiment 3

Levels of renin and aldosterone are reduced.

Levels of renin, angiotensin I and II and aldosterone are increased.

Levels of renin are increased, while those of angiotensin I and II and

aldosterone are reduced.

Levels of angiotensin I and II are increased, while that of aldosterone are

reduced.

higher $\left[\mathrm{H}^{+}\right]$; higher temperature

higher $\left[\mathrm{H}^{+}\right]$; lower temperature

lower $\left[\mathrm{H}^{+}\right]$; higher temperature

lower $\left[\mathrm{H}^{+}\right]$; lower temperature