Explanation

• Natural passive immunity occurs when antibodies are transferred naturally from mother to fetus through the placenta.
• The main antibodies transferred across the placenta are IgG antibodies.
• These antibodies provide temporary protection to the newborn against certain infections.
• The baby receives protection without producing these antibodies through its own immune system.
• Breast milk, particularly colostrum, also provides antibodies (mainly IgA) to the newborn.

Last verified on 31-10-2026

Explanation

• The vertebral column, also called the backbone or spine, is part of the axial skeleton.
• The axial skeleton forms the central supporting axis of the human body.
• It includes the skull, vertebral column, ribs, and sternum.

Additional information:

• The human vertebral column usually consists of 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), and 4 coccygeal (usually fused).

Last verified on 31-10-2026

Explanation

• Facilitated diffusion uses membrane transport proteins, such as channel or carrier proteins, to move substances from higher to lower concentration.
• This process is a type of passive transport, so it does not require cellular energy (ATP).

Additional information:

• Active transport moves substances against their concentration gradient and usually requires energy.
• Simple diffusion occurs directly through the membrane without transport proteins.

Last verified on 27-10-2026

Explanation

• The cranium is the part of the skull that encloses and protects the brain.
• It consists of 8 bones.
• These include 1 frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid, and 1 ethmoid bone.
• The human skull has 22 bones in total: 8 cranial bones and 14 facial bones.

Last verified on 31-10-2026

Explanation

• In a typical 28-day menstrual cycle, ovulation usually occurs around Day 14.
• A sharp rise in luteinizing hormone (LH), called the LH surge, triggers ovulation.
• Ovulation generally occurs about 24–36 hours after the LH surge begins.
• The released egg moves into the fallopian tube, where fertilization may occur.

Last verified on 31-10-2026

Explanation

• Monosaccharides are simple sugars, such as glucose, fructose, and galactose.
• They are absorbed through the intestinal villi into blood capillaries.
• The hepatic portal vein carries nutrient-rich blood from the digestive tract directly to the liver.
• The liver processes and regulates absorbed nutrients before they enter the general circulation.

Last verified on 31-10-2026

Explanation

Logic:

1. Parents are Blood Group A, but they have a child O [genotype ii].

    So both parents cannot be AA, they must be heterozygous: Ai x Ai

2. Cross Ai x Ai:

      AA = 25% (Group A)

      Ai = 50% (Group A)

      ii = 25% (Group O)

    So Probability of O = 1/4 = 0.25

3. Probability of being a boy = 1/2 = 0.5

4. Combined probability = P(O) x P(boy) = 1/4 x 1/2 = 1/8 = 0.125

Last verified on 31-10-2026

Explanation

• The jejunum is the middle part of the small intestine.
• It is the major site for absorption of digested nutrients into the bloodstream.
• Its inner lining contains numerous villi and microvilli, which increase the surface area for absorption.

Additional information:

• The duodenum is the first part of the small intestine and receives bile and pancreatic enzymes for digestion.

Last verified on 31-10-2026

Explanation

• IV. Overproduction and population stability: Organisms produce more offspring than can survive, but population sizes generally remain relatively constant.
• II. Struggle for existence: Limited resources create competition among organisms for food, space, and survival.
• I. Natural selection: Individuals with favourable inherited variations are more likely to survive and reproduce.
• III. Accumulation of variations: Over generations, favourable inherited variations accumulate, causing gradual evolutionary changes.
• Remember: Overproduction → Struggle for existence → Natural selection → Evolutionary change.

Last verified on 31-10-2026

Explanation

• The nucleolus is a dense region located inside the nucleus.
• It is the main site of ribosomal RNA (rRNA) synthesis and ribosomal subunit assembly.
• The ribosomal subunits are then transported to the cytoplasm.
• Ribosomes are responsible for protein synthesis.

Last verified on 31-10-2026