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.

Correct Answer: c) Parasitism

Explanation:
– Herpes simplex virus (HSV) benefits by using the human host’s cells to replicate, while the host is harmed (e.g., lesions, disease). This one-benefits/one-harmed relationship is called parasitism.
– Symbiosis (and endosymbiosis) usually implies a mutually beneficial or at least neutral long-term association, which is not the case here.
– Endoparasitism is a subtype of parasitism where the parasite lives inside the host. While HSV does live inside host cells (so it is an endoparasite), the standard term that characterizes the interaction itself is parasitism.

Correct Answer: d) Endocrine glands

Explanation:
– Hormones are chemical messengers released directly into the bloodstream.
– Endocrine glands (like pituitary, thyroid, adrenals, pancreas [islets], and gonads) secrete hormones without ducts.
– Exocrine glands use ducts to release substances like enzymes, sweat, or saliva (not hormones).
– Sebaceous glands secrete sebum (oil) into hair follicles/skin.
– While reproductive glands (gonads) do produce hormones, they are considered part of the endocrine system; the general term for hormone-secreting glands is “endocrine glands.”

Correct Answer: a) Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)

Explanation:
– PHBV is a biodegradable copolymer in the polyhydroxyalkanoate (PHA) family made by bacteria. Its full form is poly(3-hydroxybutyrate-co-3-hydroxyvalerate).
– The “co-” indicates it is a copolymer of two monomers: 3-hydroxybutyrate (HB) and 3-hydroxyvalerate (HV).
– The other options mention compounds like “veratric acid” or “vaniline,” which are unrelated aromatic compounds and not components of PHBV.

Correct Answer: a) Tetraethyllead

Explanation:
Octane rating measures a fuel’s resistance to knocking in engines. Tetraethyllead (TEL) was historically added to gasoline as an anti-knock agent to significantly increase the octane number. The other options are not standard octane-boosting additives. (Note: TEL use has been phased out in most countries due to toxicity and environmental concerns.)

Correct Answer: d) All of above

Explanation:
– Galvanized iron is coated with zinc. Oils (especially edible oils) contain free fatty acids and moisture.
– These acids react with zinc to form zinc soaps/compounds, which can be harmful (toxic) if ingested.
– The reaction also imparts off-flavors, discoloration, and accelerates rancidity, reducing oil quality.
– As zinc dissolves/reacts, the protective coating is damaged, leading to corrosion of the container.

Therefore, all listed reasons apply.

Correct Answer: b) Levonorgestrel

Explanation:
– Levonorgestrel is a synthetic progestin widely used in oral contraceptive pills and in emergency contraception. It works mainly by preventing or delaying ovulation and thickening cervical mucus.
– Vanlaflexine (venlafaxine) is an antidepressant (SNRI), not a contraceptive.
– Cholecalciferol is Vitamin D3, used for bone health and vitamin D deficiency.
– Cetrizine (cetirizine) is an antihistamine used for allergies.

Therefore, the correct choice is Levonorgestrel.

Correct Answer: c) Platinum

Explanation:
Platinum-based compounds (notably cisplatin, carboplatin, and oxaliplatin) are widely used chemotherapeutic agents for various carcinomas. They work by forming cross-links with DNA, which blocks DNA replication and transcription, leading to cancer cell death. Iron is used to treat anemia, chromium is a trace element involved in glucose metabolism, and chlorine is a disinfectant—not anticancer drugs.

Correct Answer: c) Indium tin oxide

Explanation:
“Smart film” (switchable privacy film) typically uses a PDLC (polymer-dispersed liquid crystal) layer sandwiched between two PET layers that are coated with a transparent conductive material. Indium tin oxide (ITO) is the standard transparent conductor used for these films. It allows an electric field to be applied across the PDLC, switching the film between opaque and transparent states while remaining optically clear.

The other options (zinc chloride, calcium carbonate, silica) are not transparent conductive materials and are not used as the electrode layer in smart films.

Correct Answer: c) Europium dopped strontium aluminate

Explanation:
– “Night glowing” or “glow-in-the-dark” pigments are phosphorescent materials that store light and slowly release it in the dark.
– The most common and brightest modern glow pigments are based on strontium aluminate doped with europium (often with a co-dopant like dysprosium), e.g., SrAl2O4:Eu, Dy. They have a long-lasting, bright afterglow.
– The other options are not standard persistent phosphors:
– Barium sulfate is mostly an inert filler and not used this way.
– Copper sulphide doped zinc oxide is not the classic glow system (older ones used copper-doped zinc sulfide, ZnS:Cu).
– Boron oxide doped copper sulphate is not a known night-glow pigment.