Question

Two groups of tomatoes were grown under laboratory conditions, one with compost added to the soil and one a control without the compost. The leaves of the plants grown without compost were yellowish (less green) than those of the plants growing in compost-enriched soil. The best explanation for this difference is that

• A. The compost made the soil more loosely packed, so the plants roots would grow with less resistance.
• B. The compost contained minerals such as magnesium and iron needed for the synthesis of chlorophyll.
• C. The heat released by the decomposing leaves of the compost caused more rapid growth and chlorophyll synthesis.
• D. The plants absorbed chlorophyll from the compost.

Answer 1

The correct option is B The compost contained minerals such as magnesium and iron needed for the synthesis of chlorophyll.

The compost is the organic-rich material composed of the nutrients and the source of the minerals required for the growth and development of the plants. The leaves of the plants which are enriched with the compost are green while the others are yellowish which is due to the deficiency of the minerals like the magnesium and iron which are required for the formation of the chlorophyll pigment.

Thus, the correct answer is option B.