NEET 2026 Botany Question 114 Solution

In 1770, Joseph Priestley performed bell jar experiments with a burning candle, a mouse, and a mint plant. He demonstrated that plants restore to the air whatever breathing animals and burning candles remove, establishing the fundamental role of air.

• • Priestley later discovered oxygen in 1774.

Jan Ingenhousz placed an aquatic plant (Hydrilla) in bright sunlight and darkness. He observed that in sunlight, small gas bubbles formed around green parts, but not in the dark. He identified these bubbles as oxygen, proving that sunlight and green tissues are required for oxygen release.

• • Confirmed that green parts release oxygen gas.

In 1854, Julius von Sachs provided evidence that when plants grow, they synthesize glucose, which is stored as starch. He also showed that chlorophyll is housed inside special bodies (later termed chloroplasts).

• • Established the primary organic product of photosynthesis.

Using a glass prism to split white light into spectral components, T.W. Engelmann illuminated a green alga (Cladophora) placed in a suspension of aerobic bacteria. The bacteria accumulated in blue and red light zones, plotting the first action spectrum resembling the absorption spectra of chlorophyll a and b.

• • First experimental action spectrum of photosynthesis.

Combining the milestones sequentially: Role of air (1770) -> Release of oxygen (1779) -> Production of glucose (1854) -> Absorption spectra of chlorophyll a and b (1888). This matches Option (2).

• • Matches official NTA final answer key Option B / (2).