Explanation

Solar cells convert sunlight directly into electricity using the photovoltaic effect.

They are widely used in renewable energy systems due to their efficiency and sustainability.

Explanation

Bacteria decompose organic matter from dead plants and animals, recycling nutrients back into the environment.

This process is essential for maintaining soil fertility and ecosystem balance.

Explanation

Humus is the dark organic material in soil formed by the decomposition of plant and animal matter.

It improves soil fertility by retaining moisture and nutrients essential for plant growth.

Explanation

Environmental biotechnology applies biological processes to produce renewable energy (e.g., biofuels) and improve food production sustainably.

It helps in waste management, pollution control, and developing eco-friendly agricultural practices.

Explanation

The calyx is the outermost whorl of a flower, consisting of sepals, which are usually green and leaf-like.

It protects the inner parts of the flower, especially in the bud stage, before blooming.

Explanation

A typical animal cell contains a central nucleus.

Whereas a plant cell has a cell wall and a large central vacuole.

Animal cells lack a cellulosic cell wall and large central vacuole, which are found in plant cells.

Explanation

Explanation

A meteorite is a small solid rock that survives its passage through the Earth's atmosphere and lands on the surface.

It differs from a meteoroid (before entering the atmosphere) and a meteor (which burns up in the atmosphere).

Explanation

Sublimation is the process where a solid directly changes into gas without becoming liquid.

Dry ice (solid CO₂) undergoes sublimation at room temperature.

Explanation

Sand is primarily composed of silicon dioxide (SiO₂), formed when silicon and oxygen combine.

It is a common natural material found in deserts, beaches, and riverbeds.