The correct answer is (b) Growth.
An auxanometer is a device used to measure the rate of growth of plants. It does this by measuring the change in the length of a plant part, such as a stem or root. Auxanometers are often used in research to study the effects of different environmental conditions on plant growth.
Photosynthesis is the process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen. Osmosis is the movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration. Loss of energy is a natural process that occurs in all living things. It is the result of the conversion of energy from one form to another, such as from chemical energy to heat energy.
Auxanometers are not used to measure the rate of photosynthesis, osmosis, or loss of energy.