Explanation

• The correct sequence from highest to lowest level of organization is I, VI, V, IV, III, II.

Additional information:

• I. Biosphere (Highest level, encompassing all life on Earth)
• VI. Ecosystem (Community of living organisms interacting with their physical environment)
• V. Species / Population (Group of organisms of the same kind)
• IV. Organ-system (Group of organs working together within an organism)
• III. Cell (The basic structural and functional unit of life)
• II. Atom (Lowest level, the fundamental unit of matter)

Last verified on 25-10-2026

Explanation

• Cystic fibrosis (CF) is caused by mutations in the CFTR gene, which encodes a membrane protein that transports chloride ions across cell membranes.
• Defective CFTR protein disrupts salt and water movement, producing thick, sticky mucus that commonly affects the lungs and digestive system.
• Cystic fibrosis is an autosomal recessive genetic disorder.
• It means a person generally must inherit a faulty copy of the gene from both parents to develop the disease.

Last verified on 25-10-2026

Explanation

• Thylakoids are flattened membrane sacs inside chloroplasts where the light-dependent reactions of photosynthesis occur.
• Chlorophyll in the thylakoid membranes absorbs light energy, which is converted into chemical energy stored in ATP and NADPH.

Last verified on 25-10-2026

Explanation

• Pepsin is produced in the stomach from pepsinogen and works in an acidic environment.
• Its production is primarily regulated by gastric mechanisms, not secretin.

Additional information:

• Secretin is released by the duodenum in response to acidic chyme entering from the stomach.
• It stimulates the pancreas to release bicarbonate-rich fluid, helping neutralize the acid.
• Trypsin, chymotrypsin, and pancreatic amylase are pancreatic enzymes.

Last verified on 25-10-2026

Explanation

• Chlorophyll a is blue-green.
• It is the primary photosynthetic pigment that directly participates in the light reactions of photosynthesis.
• Chlorophyll b is yellow-green.
• It acts as an accessory pigment, absorbing additional wavelengths of light and transferring the energy to chlorophyll a.
• Both pigments absorb light energy for photosynthesis, but they differ in their light-absorption spectra.

Last verified on 25-10-2026