Explanation

Explanation

• The stomach produces Hydrochloric Acid (HCl) as part of gastric juice.
• HCl creates a highly acidic environment with a pH of about 1.5–3.5.
• It activates pepsinogen into pepsin.
• Pepsin helps break down proteins into smaller peptides.

Last verified on 03-09-2026

Explanation

• Adrenal gland → Endocrine gland, not a digestive gland.
• Liver → Digestive gland; produces bile.
• Pancreas → Digestive gland; produces digestive enzymes.

Last verified on 03-09-2026

Explanation

• Bleaching powder: CaOCl₂
• Chemical name: Calcium oxychloride.
• Main uses: Bleaching and disinfection.
• CaCl₂: Calcium chloride.
• Ca(OH)₂: Calcium hydroxide (slaked lime).

Last verified on 03-09-2026

Explanation

• Marconi invented Radio.
• Radio was invented in 1895.
• Guglielmo Marconi was an Italian inventor.

Last verified on 12-08-2026

Explanation

• Alexander Graham Bell is credited as the inventor of the telephone.
• He was awarded the first successful patent for it.
• The telephone was invented in 1876.
• Bell made the first-ever telephone call to his assistant Thomas Watson.

Last verified on 31-03-2026

Explanation

• Main Cause: Freon / CFCs
• Effect: Breaks down O₃ molecules → more UV-B radiation
• Other Contributors: Halons, carbon tetrachloride
• Result: Skin cancer, cataracts, climate impact

• The Montreal Protocol (1987) aimed to reduce CFC emissions
• Ozone layer protects Earth from harmful ultraviolet rays

Explanation

• Ibn al-Haytham presented the theory of reflection and refraction of light.
• He is also known as Alhazen.
• His work, particularly his "Book of Optics", is titled Kitab al-Manazir, written during 1011–1021.
• Born: c. 965 (c. 354 AH) Basra, Buyid Emirate
• Died: c. 1040 (c. 430 AH)[1] (aged around 75) Cairo, Fatimid Caliphate

Last verified on 02-09-2026

Explanation

• Venus comes closest to Earth when it is between Earth and the Sun.

• Minimum distance: about 24 million miles (≈ 38 million km).

• This close approach occurs roughly every 584 days.

Additional Information:

• Mercury can be about 33 million miles away when Venus is on the far side of the Sun.

Last verified on 17-01-2026

Explanation

• Ozone (O₃) is mainly found in the Stratosphere, called the ozone layer.
• It absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth.
• Located roughly 15–35 km above the Earth’s surface.

Last verified on 17-01-2026