Explanation: Boron is a vital micronutrient that assists in the uptake and utilization of calcium and maintains the integrity of cell walls and membranes. It also regulates water movement in plant tissues and plays a role in pollen germination and fruit development. Deficiency of boron can lead to poor calcium translocation, brittle tissues, and reduced water absorption.

Explanation: PROLOG (Programming in Logic) is a high-level programming language widely used in the field of Artificial Intelligence (AI) and computational linguistics. It is based on formal logic and is especially useful for solving problems involving pattern matching, rule-based reasoning, and natural language processing.

Methane (CH₄) is not an allotrope of carbon. It is a chemical compound made up of one carbon atom and four hydrogen atoms. In contrast, allotropes are different structural forms of the same element in the same physical state. Carbon has several allotropes, including diamond, graphite, and fullerene (C-60), which differ in atomic arrangement and physical properties.

Other options (for context)

• Diamond: An allotrope of carbon where each carbon atom is tetrahedrally bonded to four others, making it extremely hard.
• Graphite: An allotrope of carbon with layers of hexagonally arranged atoms; good conductor of electricity.
• C-60 (Fullerene): A spherical allotrope of carbon consisting of 60 atoms arranged like a soccer ball.

Explanation: The elements Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N) — collectively known as CHON — were primarily responsible for the origin of life on Earth. These elements are the basic building blocks of all biological molecules such as proteins, nucleic acids, carbohydrates, and lipids. Early Earth's atmosphere contained these elements in gaseous forms (like CH₄, NH₃, H₂, and H₂O), which combined under lightning and UV radiation to form simple organic compounds — a process explained by the Miller–Urey experiment.

Explanation: Lysosomes are known as the ‘suicidal bags’ or ‘disposal units’ of the cell because they contain powerful digestive enzymes capable of breaking down worn-out cell parts, foreign substances, and even the entire cell when it becomes damaged or obsolete.

Explanation: The sour taste of a lemon is due to the presence of citric acid. Citric acid is a weak organic acid found naturally in citrus fruits such as lemons, oranges, and limes. It gives them their characteristic tangy flavor and also acts as a natural preservative.

Explanation: ELISA stands for Enzyme-linked immunosorbent assay. It is a biochemical test used to detect and measure antibodies, antigens, proteins, or hormones in a sample. The method relies on an enzyme-linked antigen or antibody and a color change to indicate a positive reaction.

Explanation: When a car moves forward while rain is falling vertically, the rain appears to fall at an angle relative to the car’s motion. As a result, the raindrops strike the front windscreen of the car, not the rear screen. This is due to the relative velocity between the car and the falling rain.

Explanation: The thyroid gland is the largest endocrine gland in the body. It is a butterfly-shaped gland situated in the neck region, just below the larynx. It secretes the hormones thyroxine (T₄) and triiodothyronine (T₃), which control metabolism, growth, and energy utilization. The thyroid also produces calcitonin, which helps regulate calcium levels in the blood.

Functions of the Thyroid Gland:

• Regulates metabolic rate (BMR)
• Influences growth and development
• Maintains body temperature and energy balance
• Regulates calcium metabolism via calcitonin

Disorders:

• Hypothyroidism: Leads to goitre, myxedema, or cretinism
• Hyperthyroidism: Leads to weight loss, anxiety, and increased heart rate