Explanation

The oxygen cycle is closely linked with the carbon cycle through processes like photosynthesis and respiration.

Plants release O₂ during photosynthesis (using CO₂), while animals and humans consume O₂ and release CO₂ during respiration.

Explanation

Polythene is a polymer made by linking many ethene (ethylene) monomers.

It is widely used in plastic bags and packaging materials.

Explanation

Deca (symbol: da) is the SI prefix that represents a factor of 10.

It is used to denote ten times the base unit, such as 1 decameter = 10 meters.

Explanation

Explanation

Explanation

The distance between the optical center and the principal focus is called the focal length of the lens.

while

A negative focal length indicates that the system diverges light.

Explanation

Paksat-IR was launched on August 11, 2011, as Pakistan’s first geostationary communication satellite.

It was developed with the help of China.

It provides telecommunication and broadcasting services.

Explanation

Sonorous materials produce a ringing sound when struck.

Metals are sonorous due to their ability to vibrate and transmit sound.

Explanation

Protoplasm is the living substance inside a cell, including cytoplasm and nucleus, where water makes up about 70%.

Water is essential for maintaining the structure, function, and chemical reactions in the protoplasm.

Explanation

The ostrich egg is the largest cell in the animal kingdom.

It can weigh up to 1.4 kg.