The figure given below is a diagrammatic representation of response of organisms to abiotic factors. What do A, B and C represent respectively?

The correct answer is (A) - regulator (B) - conformer  (C) - partial regulator

Explanation: 

• Regulate:  Some organisms are able to maintain homeostasis by physiological (sometimes behavioural also) means which ensures constant body temperature, constant osmotic concentration, etc.
  • All birds and mammals, and a very few lower vertebrate and invertebrate species are capable of such regulation (thermoregulation and osmoregulation).. 
  • Evolutionary biologists believe that the 'success' of mammals is largely due to their ability to maintain a constant body temperature and thrive whether they live in Antarctica or in the Sahara desert.
  • Plants, on the other hand, do not have such mechanisms to maintain internal temperatures.
• Conform: 99 percent of animals and nearly all plants cannot maintain a constant internal environment. Their body temperature changes with the ambient temperature. In aquatic animals/the osmotic concentration of the body fluids changes with that of the ambient air, water osmotic concentration. These animals and plants are simply conformers. 

Fig: Diagrammatic representation of organism response