Which of the following is difficult to measure directly?

Equipment used for the measurement of growth in plants is known as

The process of growth is determined by

Distribution of growth in a root by marking it at equal intervals with Indian ink was originally studied by

How is expansive growth characterized?

Which of the following statements are correct regarding the conditions necessary for plant growth?
i. Microelements and macroelements are required for the proper growth of the plant.
ii. For proper growth of plant,optimum temperature ranges between $15^{\circ} C-25^{\circ} C$.
iii. In the absence of oxygen,the process of respiration and release of energy takes place in all plants.
iv. Gravitational force decides the direction of growth of the shoot and root.
v. Light is essential for the germination of some seeds and photosynthesis.