Explanation

Silicon is the second most abundant element in the Earth’s crust (after oxygen).

It is commonly found in minerals like sand (silica) and quartz.

Making up approximately 27% to 28% of its mass.

Last updated 14-feb-2026

Explanation

The total percentage of silicon in the Earth's crust is approximately 27.7% by weight.

Additional information

Abundance: Second most abundant by weight (~ 28%) and volume (0.9%).

Occurrence: It does not exist in pure form in nature, but rather as oxides (e.g., sand, quartz) and silicates (e.g., feldspar, mica, clay).

Last updated 14-feb-2026

Explanation

• The genetic material (DNA) of an organism can undergo changes called mutations due to environmental factors.
• Examples of environmental factors: radiation, chemicals, UV light.
• Such changes can lead to variation in traits and sometimes evolution.

Last verified on 11-02-2026

Explanation

• Bacteria reproduce asexually mainly by binary fission, where one cell splits into two identical cells.
• This is a rapid process, allowing bacteria to multiply quickly under favorable conditions.

Last verified on 12-02-2026

Explanation

• Parturition is the process by which animals give birth to young ones.
• Marks the end of pregnancy in mammals.
• Triggered by hormonal changes in the mother.
• Ensures continuation of species.
• Observed in cows, sheep, goats, humans, and other mammals.

Last verified on 12-02-2026