Question

Photosynthesis (nourishment in light) was discovered by
A. Stephan Hales
B. Priestley
C. Ingenhousz
D. Van Mayer

Answer 1

Hint: Photosynthesis is the process by which green plants prepare their own food with the help of carbon-dioxide, water, chlorophyll and light. By this process the light energy is converted into chemical energy.

Complete Answer:
A. Stephan Hales: He discovered that green plants require sunlight for their nutrition.
B. Priestley: (i) He demonstrated that green plants purify the foul air, produced by burning of candle, and convert it into pure air.
(ii) He revealed the role of air in the growth of green plants.
(iii) He also discovered oxygen in 1774.
C. Ingenhousz: (i)He in his experiment with an aquatic plant showed that in bright sunlight, small bubbles were formed around the green parts while in dark they did not. Later he identified these bubbles to be of oxygen. Hence he showed that it is only the green part of the plant that could release oxygen.
(ii) He worked on Hydrilla plant.
(iii) He also showed that sunlight is essential for the plant that helps to purify the air fouled by the breathing of a mouse and the burning candle in priestley’s bell jar experiment.
(iv) He proposed the following equation:
\[C{O_2} + {H_2}O\xrightarrow[{Green\,\,plants}]{{Sunlight}}{O_2} + Organic\,\,matter\]
D. Van Mayer: He proposed that green plants transform light energy into chemical energy of organic matter.

Hence, the correct option is (C).

Note: Ingenhousz used a similar set up used by Priestley, but placing it once in dark and once in light.