Agriculture - 3 (B.Sc. Agriculture)

Lead is not an essential mineral element for plants. 

Exclusive photosynthesis for about an hour will lead to the formation of both sugar and starch. Hence, labelled carbon will be found in these forms together.

Paddy is a kharif crop. 

Tea cultivation requires high rainfall (150-250 cm annually), abundant sunshine, gently sloping hills (for drainage), and well-drained acidic soil. Rice requires standing water, jute needs high humidity in alluvial soil, and sugarcane grows in tropical plains with different requirements. These conditions specifically match tea estates in regions like Darjeeling and Assam.

Chloroplasts of the mesophyll cells contain grana, whereas bundle sheath chloroplasts are almost devoid of grana.

The botanical (scientific) name of sunflower is Helianthus annuus, derived from Greek 'helios' (sun) and 'anthos' (flower). Tulip, Snow berry, and Rosa are completely different plants (tulip is Tulipa, snowberry is Symphoricarpos, and rosa refers to roses).

The United States is the world's largest producer of soybeans, accounting for approximately 30-35% of global production, primarily in the Midwest (Iowa, Illinois, Minnesota). India is a significant producer but not the largest. Canada produces soybeans but ranks lower, and Bangladesh is not a major soybean producer.

Black soil (regur soil) is ideal for cotton cultivation due to its high moisture-retaining capacity and nutrient content. It's particularly found in the Deccan Plateau region, which is India's primary cotton-growing area.

Ophioglossum has the highest chromosome count of any known living organism.

 Rajasthan is the correct answer. 

Tobacco Mosaic Virus (TMV) is the classic example of a helical virus. Its RNA genome is surrounded by protein subunits arranged in a helical spiral around the nucleic acid, giving it a rod-like appearance.

 Agaricus is a genus of mushrooms containing both edible and poisonous species

Citrullus lanatus is the scientific name of watermelon.

A closed flower before blooming

True fruits develop from the ovary after fertilization. False fruits (pseudocarps) develop from other floral parts like the calyx (as in apple), thalamus (as in strawberry), or receptacle, where the ovary is incorporated into the fruit structure.