Explanation

Atmosphere is divided into Five layers/parts:

1. Troposphere
2. Stratosphere
3. Mesosphere
4. Thermosphere
5. Exosphere

Explanation

Calcium oxalate accounts for ~70% of kidney stones, forming crystals when urine is concentrated.

It results from high oxalate intake (e.g., spinach, nuts) or metabolic imbalances.

Explanation

Marijuana is derived from the dried parts (flowers, stems, seeds, leaves) of Cannabis sativa.

It contains psychoactive compounds like THC.

Explanation

A hypothesis is a testable, tentative explanation for a biological problem, based on initial observations.

It guides experiments and is later validated or refuted.

Explanation

A light microscope can magnify up to 1000x (typical maximum), resolving structures as small as 0.2 micrometers.

This is ~1000x sharper than the naked eye (which resolves ~0.2 mm).

Explanation

Lactic acid fermentation occurs in skeletal muscles during intense exercise when oxygen is scarce, converting pyruvate to lactate.

It provides rapid but temporary energy, causing muscle fatigue.

Explanation

Optimum Temperature is the specific temperature at which an enzyme exhibits peak catalytic activity.

Deviations (higher/lower) reduce efficiency, as enzymes are temperature-sensitive proteins.

Explanation

The scrotum is a sac-like structure that houses the testes (male gonads) outside the body to regulate temperature for sperm production.

It ensures optimal conditions (cooler than body temperature) for spermatogenesis.

Explanation

Veins carry blood toward the heart.

They have valves to prevent the backward flow of blood due to low pressure, especially in the limbs.

Arteries do not have valves (except at the heart).

Capillaries are too small and thin to have valves.

Explanation

طیبات سے مراد وہ چیزیں ہیں جو پاکیزہ، حلال اور جائز ہوتی ہیں۔

قرآن میں بھی "طیبات" کا ذکر حلال اور پاکیزہ کھانے کے لیے آتا ہے۔