The question asks to identify the chief pigment responsible for photosynthesis. We need to recall the different types of photosynthetic pigments and their primary roles in the process.
Correct Option: D) Chlorophyll a is the chief pigment associated with photosynthesis because it is the primary pigment that directly converts light energy into chemical energy.
The question asks to identify the scientist credited with discovering oxygen in 1774 and demonstrating that plants restore air. This requires knowledge of historical scientific discoveries related to photosynthesis and atmospheric gases.
Joseph Priestley, in 1774, conducted experiments with a candle, a mouse, and a mint plant under a bell jar. He observed that a candle would extinguish and a mouse would suffocate in a sealed jar, indicating that something in the air was being used up. He then placed a mint plant in the jar and found that the candle could burn again and the mouse could survive. This led him to conclude that plants restore the air that breathing animals and burning candles remove. He also isolated and identified oxygen gas in the same year, though he initially called it "dephlogisticated air."
C) Joseph Priestley — He is widely credited with discovering oxygen in 1774 and demonstrating that plants restore the air, which was crucial for understanding the process of photosynthesis.
The question asks to identify the scientist who demonstrated the necessity of sunlight for the purifying action of green plants on air. This refers to early experiments on photosynthesis, specifically the role of light.
D) Jan Ingenhousz demonstrated that sunlight is essential for the purifying action of green plants on air. He showed that only the green parts of plants, in the presence of sunlight, release oxygen.
The question asks to identify the scientist who first provided evidence for the production of glucose during plant growth. This requires knowledge of the historical development of photosynthesis research and the contributions of key scientists.
C) Julius von Sachs — In 1862, Julius von Sachs demonstrated that glucose is produced in plants, usually stored as starch, and that chlorophyll is located in specialized structures within plant cells. This was the first clear evidence of glucose production during plant growth.
The question asks to identify the scientist who first described the action spectrum of photosynthesis using a specific experimental setup involving Cladophora and aerobic bacteria. This requires knowledge of key historical experiments in photosynthesis.
Correct Option: D) T. W. Engelmann — He performed the classic experiment using a prism to split light, a filamentous alga (Cladophora), and aerobic bacteria to plot the first action spectrum of photosynthesis. He observed that bacteria accumulated primarily in the blue and red regions of the spectrum, indicating maximum oxygen evolution and thus maximum photosynthetic activity at these wavelengths.
The question asks to identify the scientist who demonstrated that the oxygen released during photosynthesis originates from water, using studies on purple and green sulfur bacteria. This requires knowledge of key experiments in the history of photosynthesis research.
Correct Option: D) Cornelius van Niel conducted studies on purple and green sulfur bacteria, observing that they release sulfur instead of oxygen when using \(\text{H}_2\text{S}\) as a hydrogen donor. This led him to propose that the oxygen released during plant photosynthesis comes from water, not carbon dioxide.