Explanation: When a ship floats on water, it displaces a volume of water whose mass is equal to the mass of the ship. This is in accordance with Archimedes’ Principle, which states that an object floats when the buoyant force (equal to the weight of displaced fluid) balances its own weight.

Explanation: The DNA sequencing technique was developed by Frederick Sanger in 1977. His method, known as the Sanger chain termination method, determines the nucleotide sequence of DNA using labeled dideoxynucleotides (ddNTPs) that terminate DNA chain elongation. This technique revolutionized molecular biology and became the foundation for genome sequencing projects such as the Human Genome Project.

Explanation: Prithvi was the first indigenously developed missile of India, designed under the Integrated Guided Missile Development Programme (IGMDP) launched in 1983 by the Defence Research and Development Organisation (DRDO). It is a surface-to-surface short-range ballistic missile (SRBM) capable of carrying both conventional and nuclear warheads. The Prithvi missile series includes Prithvi-I (Army version), Prithvi-II (Air Force), and Prithvi-III (Navy), with ranges varying from 150 km to 350 km.

Explanation: Humidity is a measure of the amount of water vapour (moisture) present in the air. It indicates how saturated the air is with moisture and affects weather, comfort, and precipitation. High humidity means the air contains more water vapour, while low humidity indicates dry air.

Explanation: A barometer is an instrument used primarily for measuring atmospheric pressure. It helps in weather forecasting and determining altitudes (since atmospheric pressure decreases with height). A mercury barometer consists of a glass tube filled with mercury inverted in a mercury reservoir. When air pressure changes, the height of the mercury column changes accordingly. However, a barometer cannot measure the density of a liquid — that function is performed by a hydrometer.

Explanation: The habitat of an organism is its natural living place where it finds food, water, shelter, and mates for reproduction. Examples include a pond for a frog, soil for an earthworm, and forest for a tiger. Each species has a specific habitat suited to its survival needs. The niche, on the other hand, describes the organism’s role or function in that habitat, such as how it obtains food or interacts with others.

Explanation: Amniocentesis is a medical diagnostic procedure used to determine the genetic and chromosomal makeup of a developing fetus. It involves the withdrawal of a small amount of amniotic fluid from the uterus using a fine needle. This fluid contains fetal cells that can be tested to identify genetic disorders such as Down’s syndrome and also to determine the sex of the fetus. However, using amniocentesis for sex determination is illegal in India under the Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act to prevent female foeticide.