Correct Answer: d) Increased mineral absorption and diseases protection

Explanation:
– In a mycorrhizal association, the fungus extends the root’s effective surface area, improving uptake of minerals (especially phosphorus) and water.
– The fungus also helps protect the plant from certain soil pathogens, enhancing disease resistance.
– The plant, in turn, provides carbohydrates (food) to the fungus. So option b (Food) is not an advantage to the plant.
– Hence, option d best describes the plant’s benefits.

Correct Answer: c) 16th September

Explanation:
– World Ozone Day (International Day for the Preservation of the Ozone Layer) is observed on 16 September to commemorate the signing of the 1987 Montreal Protocol on substances that deplete the ozone layer.
– 5 June is World Environment Day, 21 April is not Ozone Day (UN: World Creativity and Innovation Day; in India: Civil Services Day), and 5 December is World Soil Day/International Volunteer Day.

Correct Answer: b) Mesocarp

Explanation:
– Mango is a drupe (stone fruit) with a pericarp divided into three layers.
– Epicarp = outer skin (not eaten).
– Mesocarp = thick, fleshy, sweet pulp (the part we eat).
– Endocarp = hard, stony layer around the seed (not eaten).

Correct Answer: c) A P de Condolle

Explanation:
A. P. de Candolle (often spelled de Condolle) was the first to classify plants using the presence or absence of vascular tissues (xylem and phloem) as a key criterion. He divided plants into:
– Vasculares (with vascular bundles) — including pteridophytes and seed plants
– Cellulares (without vascular bundles) — including non-vascular groups

Bentham & Hooker and Engler & Prantl used broader morphological and evolutionary features, but they were not the first to base a major division on vascular tissue characteristics.

Correct Answer: c) Transport of water and dissolved minerals

Explanation:
– Xylem is the plant vascular tissue that conducts water and dissolved mineral salts from the roots to the stems and leaves, mainly driven by transpiration pull and cohesion-tension.
– Option b and d are functions of phloem, which transports food (sugars) and many organic molecules including amino acids.
– Gases like oxygen and carbon dioxide move mostly by diffusion through stomata and lenticels, not via xylem (option a).

Correct Answer: c) Sugarcane

Explanation:
– Kharif (monsoon) crops are sown with the onset of rains (around June–July) and need warm, humid conditions.
– Sugarcane thrives in such warm and moist conditions and is commonly treated as a Kharif/cash crop in many regions.
– The other options—gram, barley, and wheat—are classic Rabi crops, sown in winter (Oct–Dec) and harvested in spring.

Correct Answer: a) Endangered

Explanation:
– Endangered species are those that are in immediate danger of extinction in the near future.
– Rare: species with small populations but not currently at high risk.
– Vulnerable: species likely to become endangered if threats continue.
– Extinct: species that no longer exist.

Correct Answer: c) UAA

Explanation:
– Nonsense codons (stop codons) signal termination of protein synthesis and do not code for any amino acid. The three stop codons are UAA, UAG, and UGA.
– UAA is one of these stop codons.
– By contrast:
– UUU codes for phenylalanine (sense codon).
– AUG is the start codon and codes for methionine.
– UGC codes for cysteine (sense codon).

Correct Answer: a) Lipids and proteins in varying combinations which are specific to each species, cell type and organelle

Explanation:
– Biological membranes follow the fluid mosaic model: a phospholipid bilayer with embedded and peripheral proteins.
– Carbohydrates are also present, attached to lipids and proteins (glycolipids and glycoproteins), but the core components are lipids and proteins.
– The lipid-to-protein ratio varies by species, cell type, and organelle (e.g., myelin is lipid-rich, while the inner mitochondrial membrane is protein-rich).
– Therefore, options “lipids only” or “proteins only” are incorrect.

Correct Answer: a) IgM

Explanation:
– In a primary immune response, naive B cells initially produce and secrete IgM because they first express membrane-bound IgM (and IgD).
– Only later, with T-cell help, do B cells undergo class-switch recombination to produce other antibodies like IgG, IgA, or IgE.
– IgM is typically a pentamer, giving it high avidity and making it very effective at early neutralization and complement activation.