Explanation

• Birds, snakes and fish belong to Kingdom Animalia.
• Animals are multicellular eukaryotes, meaning their cells contain a true nucleus and membrane-bound organelles.
• Animal cells lack a cell wall and obtain food from other organisms, so they are heterotrophs.
• Animals do not contain chlorophyll and cannot make their own food through photosynthesis.

Last verified on 02-11-2026

Explanation

• Non-renewable resources are available in limited quantities and cannot be replenished within a short period.
• Coal, petroleum, and natural gas are fossil fuels formed from ancient organic matter over millions of years.
• Metals such as iron and copper are obtained from mineral ores.
• They are considered non-renewable resources.
• Conservation, recycling, and efficient use help reduce the depletion of these resources.

Last verified on 02-11-2026

Explanation

• Only about 2.5% or 0.025 (3%) of the water on Earth is freshwater, which is vital for human consumption, agriculture, and ecosystem health.
• The remaining 97.5% (97%) is saltwater, found in oceans, seas, and salt lakes.

Last verified on 02-11-2026

Explanation

• A sarcomere is the basic structural and functional contractile unit of a myofibril.
• It extends from one Z-line to the next Z-line and contains actin (thin) and myosin (thick) filaments.
• During muscle contraction, these filaments slide past one another, shortening the sarcomere.
• Sarcomeres give skeletal and cardiac muscles their characteristic striped appearance.

Last verified on 02-11-2026

Explanation

• The humerus (upper arm bone) forms a ball-and-socket joint with the scapula (shoulder blade).
• The rounded head of the humerus fits into the glenoid cavity of the scapula, allowing movement in multiple directions.
• The shoulder joint provides a wide range of movement, including rotation, flexion, and extension.
• The hip joint is also a ball-and-socket joint, formed by the femur and the hip bone.

Last verified on 02-11-2026

Explanation

• In skeletal muscle, each thick myosin filament is surrounded by six thin actin filaments in the hexagonal arrangement.
• Myosin forms the thick filaments, while actin forms the thin filaments in muscle fibres.
• During muscle contraction, myosin interacts with actin to produce movement through the sliding filament mechanism.

Last verified on 02-11-2026

Explanation

• Total Vertebrae: 33
• Cervical Vertebrae: 7
• Thoracic Vertebrae: 12
• Lumbar Vertebrae: 5
• Sacral Vertebrae: 5 (fused) and Coccygeal Vertebrae: 4 (fused)

Additional information:

• Total bones in an adult: 206
• Bones in a newborn: About 300
• Longest bone: Femur
• Shortest bone: Stapes
• Bones in the skull: 22
• Bones in one hand: 27

Last verified on 21-07-2026

Explanation

• ADH is also called Vasopressin.
• It is released from the posterior pituitary gland.
• During dehydration, ADH secretion increases to help the kidneys reabsorb more water.
• It reduces water loss through urine and makes urine more concentrated.
• ADH helps maintain the body's water balance (osmoregulation).

Last verified on 02-11-2026

Explanation

• Xerophytes are plants adapted to survive in dry and desert environments.
• They have adaptations to reduce transpiration (water loss through leaves).
• Thick waxy cuticles, reduced leaf size, and sunken stomata help conserve water.
• Examples include cactus, aloe vera, and date palm.

Last verified on 02-11-2026

Explanation

• Osmoregulation is the process of regulating water and dissolved solute concentrations in cells and body fluids.
• It maintains the proper balance of water and salts inside cells.
• In humans, the kidneys play a major role in osmoregulation by controlling water and salt levels.
• Osmoregulation helps maintain the body's internal balance (homeostasis).

Last verified on 02-11-2026