Explanation

• The intensity of a stimulus in the brain is detected by the frequency of nerve impulses. 
• A stronger stimulus produces a higher number of action potentials per second.

Additional information:

• The brain interprets stimulus strength by impulse frequency, not impulse size
• Common in sensory neurons (touch, pain, sound)

Last verified on 15-01-2026

Explanation

In plant cells, the Calvin cycle occurs in the stroma of the chloroplast.

Additional information:

• Discovered by: Melvin Calvin
• Phase of Photosynthesis: Dark reaction (light-independent)
• Main Function: Conversion of CO₂ into glucose
• Energy Used: ATP and NADPH

Last verified on 15-01-2026

Explanation

• Protein-coding DNA: ~1.5–2% of the human genome
• Total genes: ~20,000–21,000 protein-coding genes
• Non-coding DNA: ~98% (regulatory, introns, repetitive sequences)
• Genome size: ~3 billion base pairs

Additional information:

• Non-coding DNA plays roles in gene regulation and expression
• Earlier called “junk DNA,” now known to have important biological functions

Last verified on 15-01-2026

Explanation

Explanation

Oxygen constitutes about 21%, or more precisely 20.95%, of the Earth's atmosphere by volume

Present about one-fifth of the air.

Supports respiration.

Needed for combustion.

Maintains balance in the atmosphere.

Explanation

Heat from the Sun reaches Earth through radiation

It is the transfer of energy via electromagnetic waves (like infrared, visible light, UV) 

Sunlight takes an average of 8 minutes and 20 seconds to travel from the Sun to the Earth.

Explanation

Ethnology is the branch of science that deals with the study of races, cultures, and ethnic groups of humans.

The study of human races, particularly their physical characteristics, origins, and distribution

Explanation

The vitamins not stored in the human body are Vitamin C and most B-complex vitamins

 Because they dissolve in water, the kidneys filter out what isn't immediately used, preventing buildup and toxicity but necessitating daily replenishment. 

Vitamin C (Ascorbic Acid): Essential for collagen and immune function, but any surplus is flushed out. 

B Vitamins (except B12): Includes Thiamin (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Pyridoxine (B6), Biotin (B7), and Folate (B9). 

Explanation

Breakbone fever is another name for Dengue.

It is a viral disease transmitted by Aedes mosquitoes.

It causing severe joint and muscle pain.

Explanation

300 grams is the weight of the heart of an adult human being.

The average gross weight of the heart was  for men 289.6 g

The average gross weight of the heart was  for women 284.7 

At the age of 61-70 years, the average weight of men was 345.9

At the age of 61-70 years, the average weight of women was 285.1

*****ٓAdditional Informations*****

A human brain weight is 1400 grams.