Answer: C

Explanation:

Cetaceans are exclusively aquatic mammals (including whales, dolphins, porpoises, etc.) that constitute the order Cetacea. They are found in oceans and some freshwater environments throughout the world. Hence statement 1 is correct.

Their body is narrow/thin, there is no external hind limb and the tail ends in the form of a triangular pointed part of a two-part or horizontal blade. Cetaceans have to come to the surface of the water to breathe through blowholes located on top of their heads. Hence statement 2 is correct.

Answer: D

Explanation:

Methane hydrate is an ice-like substance that forms at low temperatures and high pressure. They are found in four of Earth's environments:

Sediments and sedimentary rock units beneath Arctic permafrost, sedimentary deposits along continental margins, deep-water sediments of inland lakes and seas, and beneath Antarctic ice. Methane hydrates are stable at low temperatures, but they can break down if the water and ocean floor warm. When this happens, microorganisms oxidize the resulting methane gas to form carbon dioxide (CO2).

Methane hydrates are found primarily near continental margins at water depths between 350 and 5000 metres. They are also found in the deeper parts of the continental shelf, where they remain stable in cold, high-pressure conditions. An estimated 99% of gas hydrates are found in sediments of marine continental margins. The remaining 1% is associated with sediments mostly in and beneath high-latitude, areas of persistent permafrost.

Answer: C

Explanation:

Plastic microbeads are small pieces of plastic that are used as an exfoliating agent to help remove dead skin cells and soften the skin. They are found in products such as:

Facial cleansers, body scrubs, toothpaste, hand wash, shampoo, nail polish, sunscreen, deodorant, lipstick, eyeliner, shower gel, etc. Microbeads are used as a replacement for natural exfoliating ingredients like pumice, oatmeal or walnut husks. However, plastic microbeads are a major environmental concern, as they are too small to be filtered out by wastewater treatment plants and can end up in our oceans and waterways.

Answer: B

Explanation:

NISAR (NASA-ISRO Synthetic Aperture Radar) is a Low Earth Orbit (LEO) observatory jointly developed by NASA and ISRO. It is an SUV-sized satellite weighing 2,800 kg. Hence statement 1 is not correct.

NISAR includes both L-band and S-band synthetic aperture radar (SAR) instruments, making it a dual-frequency imaging radar satellite. It will be the first satellite mission to use two different radar frequencies (L-band and S-band) to measure changes in our planet's surface. Hence statement 2 is correct.

Answer: C

Explanation:

Nipah virus (NiV) is a zoonotic virus, which can spread between animals and people. It was first discovered in the year 1999 after spreading in Malaysia and Singapore. Nipah virus first spread in Malaysia and Singapore in 1998 and 1999. The virus is spread primarily through fruit bats, but can also spread through other animals, including pigs and humans.

The outbreak resulted in nearly 300 cases and more than 100 deaths. The disease is spread by fruit bats or 'flying foxes' of the genus Pteropus, which are the natural reservoir hosts of Nipah and Hendra viruses. The virus is present in bat urine and possibly bats feces, saliva, and birth fluids.