Explanation: A strong-smelling compound called thioethanolamine (or ethyl mercaptan) is added to LPG (liquefied petroleum gas) to help detect gas leaks. LPG itself is odourless, so this compound gives it a distinct unpleasant smell, making leakage easily noticeable for safety.

Explanation: The speed of internet connectivity is expressed in Megabits per second (Mb/sec or Mbps). It indicates how much data is transferred per second over a network connection. One megabit equals 1,000,000 bits. Higher Mbps values mean faster internet speeds. For example, a 100 Mbps connection can transfer 100 million bits of data every second. Note that 1 byte = 8 bits, so internet speeds in Mbps differ from file sizes, which are usually measured in megabytes (MB).

Explanation: Dengue fever is caused by the Dengue virus, which belongs to the Flavivirus group. It is transmitted to humans through the bite of an infected Aedes aegypti mosquito. The virus multiplies in the blood and causes symptoms such as high fever, severe headache, joint and muscle pain, rashes, and low platelet count. In severe cases, it can lead to Dengue hemorrhagic fever or Dengue shock syndrome. Prevention includes controlling mosquito breeding and avoiding mosquito bites.

Explanation: Tuberculosis (TB) is not a viral disease; it is caused by a bacterium called Mycobacterium tuberculosis. In contrast, Polio, Swine flu, and Hepatitis are viral diseases caused by different types of viruses.

Explanation: The time period of a simple pendulum is given by the formula T = 2π√(L/g), where L is the length of the pendulum and g is the acceleration due to gravity. Since the Moon’s gravity is about 1/6th of Earth’s, the value of g decreases, causing the time period to increase.

Explanation: Bullets are typically made of lead or lead alloys because lead is dense and malleable. When bullets remain lodged in the body, they can corrode over time and release lead ions into surrounding tissues and blood, resulting in chronic lead poisoning (plumbism). Symptoms include abdominal pain, anemia, fatigue, headache, irritability, and neurological disorders. In severe cases, it may cause kidney and brain damage.

Prevention: Complete removal of bullet fragments and regular monitoring of blood lead levels in affected individuals are essential to prevent toxicity.

Explanation: Mitochondria are double-membraned organelles found in almost all eukaryotic cells. They are known as the 'power house of the cell' because they generate adenosine triphosphate (ATP) through the process of cellular respiration. The inner membrane forms folds called cristae, which increase the surface area for enzyme activity related to energy production. Mitochondria also contain their own DNA and ribosomes, enabling them to produce some of their own proteins.

Key Reaction:

Glucose + Oxygen → Carbon dioxide + Water + ATP

Explanation: Liquid Natural Gas (LNG) predominantly contains methane (CH₄) in liquid form. It is produced by cooling natural gas to about −162°C, which reduces its volume for easier storage and transportation. LNG is a clean fuel with high energy efficiency and low emissions.