Growth in length of a plant can be measured by

Study the following statements:
$I.$ $O_2$ helps in releasing metabolic energy,which is essential for growth.
$II.$ Nutrients are required by plants for the synthesis of protoplasm.
$III.$ Change in temperature could be detrimental for the survival of an organism.
$IV.$ Light and gravity do not affect the stages of growth.
Choose the correct option.

In the figure of the sigmoid growth curve given below,label segments $1$,$2$,and $3$.

Sleep movements of leaves in certain plants or photonasty is due to:

Explain the factors affecting growth.

Find out the correct statement$(s)$.
$(a)$ Growth in plants is internal/intrinsic and open-ended.
$(b)$ Formation of cellular materials is called real or protoplasmic growth.
$(c)$ Plant growth is diffused only during the early embryonic stage.