Explanation

The human urinary system functions as a sequence of organs that filter blood and eliminate waste in a specific order: 

1. Kidney: The starting point where blood is filtered and urine is formed.
2. Ureter: Narrow, tubular structures that transport the formed urine from the kidneys down to the bladder.
3. Urinary Bladder: A muscular sac in the pelvic cavity that acts as a temporary storage reservoir for urine.
4. Urethra: The final canal-shaped tube through which urine is expelled from the body to the exterior.

Last verified on 11-04-2026

Explanation

• Snakes normally control the population of primary consumers.
• When snakes decrease, predation pressure reduces.
• As a result, primary consumers (like rodents, insects) increase.
• This can disturb ecological balance in the desert ecosystem.

Last verified on 11-04-2026

Explanation

• This condition is caused by nondisjunction during meiosis.
• Homologous chromosomes fail to separate properly in meiosis I (or sister chromatids in meiosis II).
• As a result, one gamete gets an extra chromosome.
• After fertilization, this leads to trisomy 21 (Down syndrome).

Last verified on 11-04-2026

Explanation

• Lamarckism is an early evolutionary theory proposed by Jean-Baptiste Lamarck.
• It states that organs become stronger if used and weaker if not used.
• These acquired characteristics were believed to be passed to offspring
• For example, stretching of giraffe neck over generations.
• Hence, it is based on use and disuse of organs.

Last verified on 12-04-2026

Explanation

• Competitive inhibition occurs when a substance similar to the substrate competes for the enzyme’s active site.
• Chemical X blocks the active site, stopping product formation.
• Increasing substrate concentration overcomes this effect.
• This restores enzyme activity.
• Therefore, this is competitive inhibition.

Last verified on 12-04-2026

Explanation

• When a sudden disaster drastically reduces a population size, it causes a loss of genetic variation.
• This random reduction is known as the bottleneck effect.
• The surviving population may not represent the original genetic diversity.
• It often leads to inbreeding and reduced adaptability.
• This is common in isolated populations like islands.

Last verified on 12-04-2026

Explanation

• Amoeba engulfs food particles through phagocytosis.
• This shows that protists cannot make their own food.
• Instead, they depend on other organisms for nutrition.
• Such organisms are called heterotrophs.
• Therefore, protists are capable of heterotrophic nutrition.

Last verified on 12-04-2026

Explanation

• Cellular respiration usually begins with glycolysis, where glucose is broken down into pyruvate.
• If glucose is replaced with fatty acids, glycolysis cannot function in the same way.
• Fatty acids are broken down through different pathways (like beta-oxidation) before entering respiration.
• Therefore, the first and directly affected stage is glycolysis.
• It is the main entry point for glucose metabolism.

Last verified on 12-04-2026

Explanation

• Plant cells contain a large central vacuole that stores water, nutrients, and waste.
• In the carrot root cell, the prominent vacuole confirms it is a plant cell.
• Animal cells usually have small or no vacuoles.
• This feature helps maintain cell turgidity and support plant structure.
• Therefore, the observed cell is a plant cell.

Last verified on 12-04-2026

Explanation

• Dialysis is used when kidneys fail to function properly.
• It removes waste products, excess water, and salts from the blood.
• This process replaces the natural function of kidneys.
• Therefore, dialysis performs the function of excretion in the body.
• It helps maintain blood balance and prevents toxic buildup.

Last verified on 12-04-2026