Mars has two natural satellites, Phobos and Deimos. These moons were discovered in 1877 by astronomer Asaph Hall. They are small, irregularly shaped bodies, believed to be captured asteroids or formed from debris. Phobos is the larger moon and orbits very close to Mars, completing a revolution in about 7 hours. Deimos is smaller and orbits farther away, taking about 30 hours. Unlike Earth, which has one moon, and Mercury and Venus, which have none, Mars has two moons. This makes option B correct. These moons are of great scientific interest because they provide clues about the formation and evolution of the solar system. Future missions may explore them further. Thus, the correct answer is 2.

The term “bit” is short for “binary digit,” which is the smallest unit of data in computing and digital communications. A bit can have only two possible values: 0 or 1. These values represent the fundamental building blocks of all digital systems, including computers, smartphones, and communication networks. Bits are used to represent data in binary form because electronic systems operate using two states, such as on/off or high/low voltage. Multiple bits are combined to form larger data units such as bytes (8 bits), kilobytes, megabytes, and so on. Understanding bits is essential for grasping how computers process, store, and transmit information. Higher-level data like text, images, and videos are all ultimately encoded in binary form using bits. Other options are incorrect because they do not represent the standard definition of “bit.” Thus, binary digit is the correct answer, forming the foundation of all modern computing systems.

The ureter is a tube that connects each kidney to the urinary bladder. Its primary function is to transport urine produced in the kidneys to the bladder for storage before excretion. Each person has two ureters, one from each kidney. Urine moves through the ureters by peristaltic movements, which are wave-like contractions of the muscular walls. The urethra is a different structure that carries urine from the bladder to the outside of the body. The nephron is the functional unit of the kidney responsible for filtering blood. Urination is a process, not a structure. Thus, ureter is the correct answer. Understanding the urinary system is important for studying human physiology and maintaining health awareness.

Smooth ER synthesizes lipids such as phospholipids and steroids. It also helps in detoxification. Protein synthesis occurs in rough ER, not smooth ER.

This UN day is observed on 17 June to raise awareness about desertification and drought issues worldwide.