(d) All four
Microsatellite DNA, also known as short tandem repeats (STRs) or simple sequence repeats (SSRs), is a type of genetic marker that consists of repeating sequences of DNA. These repeating units, which are typically 1-6 base pairs in length, are repeated in tandem, and the amount of repetitions varies between individuals.
The number of repeats at a certain microsatellite locus might vary greatly between people in a population because microsatellite DNA is highly variable.
It is commonly used in genetic studies, including population genetics and phylogenetic analysis (the study of how a species or group of organisms evolves), to study relationships among different species of fauna.
Microsatellites are highly polymorphic and vary in length due to differences in the number of repeat units. By analyzing the variations in microsatellite DNA sequences among individuals or populations, researchers can assess genetic diversity, population structure, and evolutionary relationships within and between species.
Uses of Microsatellite DNA
DNA fingerprinting: Microsatellite DNA can be used to create a unique DNA fingerprint for an individual. This can be used for forensic identification, paternity testing, and other purposes.
Genetic mapping: Microsatellite DNA can be used to map the location of genes in the genome. This can be used to identify genes that are associated with diseases or other traits.
Population genetics: Microsatellite DNA can be used to study the genetic diversity of populations. This can be used to understand how populations have evolved and to identify populations that are at risk of extinction.
Conservation genetics: Microsatellite DNA can be used to study the genetic diversity of endangered species. This information can be used to develop conservation strategies for these species.

(a) Only one
Cepheids, also called Cepheid Variables, are stars which brigthen and dim periodically. This behavior allows them to be used as cosmic yardsticks out to distances of a few tens of millions of light-years. The brighter the Cepheid, the longer its period. In fact, Cepheids are very special variable stars because their period (the time they take to brighten, dim and brighten again) is regular (that is, does not change with time), and a uniform function of their brightness. That is, there is relation between the period and brightness such that once the period is known, the brightness can be inferred. (1st Pair is incorrect)
A nebula is a giant cloud of dust and gas in space. Some nebulae (more than one nebula) come from the gas and dust thrown out by the explosion of a dying star, such as a supernova. Other nebulae are regions where new stars are beginning to form. For this reason, some nebulae are called “star nurseries.” (2nd Pair is incorrect)
Pulsars are neutron stars. Pulsars are rotating neutron stars observed to have pulses of radiation at very regular intervals that typically range from milliseconds to seconds. A pulsar is the crushed core of a massive star that ran out of fuel, collapsed under its own weight and exploded as a supernova. (3rd Pair is incorrect)

(a) Only one
LISA- Laser Interferometer Space Antenna.
It is a laser interferometric gravitational wave observatory in space with 3 spacecraft in heliocentric orbit and million km arm length.
eLISA is a mission aiming at exploring the Gravitational Universe from space for the first time. It involves scientists from eight European countries- Denmark, France, Germany, Italy, The Netherlands, Spain, Switzerland, and the UK as well as the support of several US-based ones.
The evolved Laser Interferometer Space Antenna (eLISA) is a mission led by the European Space Agency to detect and accurately measure gravitational waves, tiny ripples in the fabric of space-time from astronomical sources. LISA would be the first dedicated space-based gravitational wave detector. It aims to measure gravitational waves directly by using laser interferometry. (Statement 1 is incorrect)
These gravitational waves are emitted by the supermassive black holes that reside in the centres of many galaxies. In addition, eLISA will measure the signals of thousands of compact binary star systems in the Milky Way.

(d) None
Nuclear fusion occurs when two or more lighter nuclei combine to form a single stable and heavy nucleus. The process releases energy because the total mass of the resulting single nucleus is less than the mass of the two original nuclei. The leftover mass becomes energy.
Fusion occurs when two atoms slam together to form a heavier atom, like when two hydrogen atoms fuse to form one helium atom. This is the same process that powers the sun and creates huge amounts of energy—several times greater than fission. It also doesn’t produce highly radioactive fission products.
The splitting of a heavy nucleus into two or more lighter nuclei is known as nuclear fission. This results in a loss in mass, as well as exothermic energy and neutron emission. Fission elements are nuclei that emit two to three neutrons per nucleus. Uranium and plutonium are most commonly used for fission reactions in nuclear power reactors because they are easy to initiate and control.
Nuclear fission is used to produce nuclear energy, while technology to generate electricity from fusion is still in the research and development phase. Nuclear fission is a physical process that releases a large amount of energy from atoms. In this process, a neutron collides with a uranium atom, splitting it and releasing a large amount of energy in the form of heat and radiation. The energy released by fission heats water into steam, which spins a turbine to produce electricity.
A nuclear holocaust is a theoretical scenario where the detonation of nuclear weapons causes widespread destruction and radioactive fallout. It is also known as a nuclear apocalypse, nuclear annihilation, nuclear armageddon, or atomic holocaust. The radioactive waste is expected to hang like a cloud in the earth’s atmosphere in the event of a nuclear holocaust. The sun’s radiation will be absorbed, resulting in a nuclear winter.

(a) Only one
India’s nuclear technology is developed and managed by several organizations
1. Department of Atomic Energy (DAE): The DAE is the nodal agency for the formulation and implementation of policies and programs for nuclear power development in India. (Statement 1 is incorrect)
2. Nuclear Power Corporation of India Limited (NPCIL): NPCIL is a public sector undertaking responsible for the design, construction, operation, and maintenance of nuclear power plants in India. (Statement 2 is incorrect)
3. Bhabha Atomic Research Centre (BARC): BARC is the premier research and development institution for nuclear science and technology in India. (Statement 3 is correct)
**The Nuclear Command Authority (NCA) of India is the authority responsible for command, control and operational decisions regarding India’s nuclear weapons programme. It comprises a Political Council headed by the Prime Minister of India and an Executive Council headed by the National Security Advisor.