Explanation: Dissolved oxygen (DO) is the amount of oxygen available in water for aquatic organisms to breathe. For the healthy survival of most aquatic life, the DO level should be between 4 and 6 mg/L. Levels below 3 mg/L can lead to stress or suffocation, especially for fish and aerobic microorganisms. Higher DO levels are typical of clean, cold, and well-aerated waters, while polluted or stagnant waters often have lower oxygen levels due to organic decay.

Factors Affecting DO Levels:

• Temperature (higher temperature = lower DO)
• Organic pollution and bacterial activity
• Photosynthesis by aquatic plants and algae
• Water turbulence and aeration

Explanation: An F1 (Formula One) car is primarily made of carbon fibre, a lightweight yet extremely strong and durable material. Carbon fibre provides high strength-to-weight ratio, excellent rigidity, and improved safety — essential for achieving high speeds and ensuring driver protection in racing conditions.

Explanation: The decibel (dB) is a unit used to measure the intensity or loudness of sound. It expresses sound level on a logarithmic scale relative to a standard reference intensity of 10^-12 watt/m², which is the faintest sound the average human ear can hear. Normal conversation is around 60 dB, city traffic about 80–90 dB, and sounds above 120 dB can cause pain or hearing damage. The decibel scale helps compare very large variations in sound intensity conveniently.

Explanation: Coriander (Coriandrum sativum) is a herb belonging to the family Apiaceae. The leaves are used as a fresh herb (commonly known as cilantro), and the dried fruits (often referred to as coriander seeds) are used as a spice. The fruits contain essential oils like linalool and borneol, which give coriander its characteristic aroma and flavor.

Uses:

• Leaves — used in cooking for flavoring and garnishing dishes.
• Dried fruits (seeds) — used as a spice, in curry powders, and for medicinal purposes (digestive aid).

Explanation: A parity bit is added to binary data in a computer system for error detection. It helps identify whether data has been altered during transmission or storage. The parity bit makes the total number of 1s either even (even parity) or odd (odd parity), allowing simple error checking.

Explanation: The Montreal Protocol, signed in 1987, is an international agreement aimed at protecting the ozone layer by phasing out the production and use of ozone-depleting substances (ODS) such as chlorofluorocarbons (CFCs) and halons. It is one of the most successful environmental treaties in history.

Ocean Thermal Energy (OTE) is produced due to the temperature difference at different levels in the ocean. The surface water is warmer because it absorbs sunlight, while the deeper layers remain cold. This temperature gradient is used to run a heat engine that generates electricity — a process known as Ocean Thermal Energy Conversion (OTEC).

• Tides: Related to gravitational pull, not temperature.
• Pressure difference: Exists but not used for energy generation.
• Waves: Used in wave energy systems, not OTEC.