Explanation

Centripetal force acts perpendicular to the direction of motion, so it does no work.

Work = Force × Displacement × cos(θ); since θ = 90°, cos(90°) = 0, so Work = 0.

Explanation

Sunlight provides the energy that plants use during photosynthesis to produce food.

It is the primary source of energy in almost all ecosystems.

Explanation

Germination is the process where a seed begins to grow and develop into a new plant.

It starts when the seed absorbs water, swells, and the embryo begins to sprout.

Explanation

Root hairs increase the surface area of roots for efficient absorption of water and minerals from the soil.

They play a key role in anchoring the plant and facilitating nutrient uptake.

Explanation

Chloroplast contains chlorophyll.

It is the site where photosynthesis takes place in plant cells.

It converts light energy into chemical energy (glucose) using carbon dioxide and water.

Explanation

Iron (Fe), Sodium (Na), and Calcium (Ca) are essential minerals required for bodily functions (e.g., hemoglobin, nerve transmission, bone health).

Iodine (I) is a trace element, not classified as a mineral, though it’s vital for thyroid function.

Explanation

Endocardium lines the inner chambers of the heart.

Myocardium is the thick, muscular middle layer responsible for contraction.

Epicardium is the outermost protective layer.

Together, these three layers make up the complete structure of the heart wall.

Explanation

Echinodermata (like starfish, sea urchins) are marine animals and do not include parasites.

In contrast, groups like Nematoda, Platyhelminthes, and Protozoa include many parasitic species.

Explanation

These lines are taken from "Elegy Written in a Country Churchyard" by Thomas Gray.

The stanza reflects on the unrecognized potential of people buried in a quiet graveyard — possibly capable of greatness but lost to obscurity.

Explanation

These lines are from the poem by G. Allana (Ghulam Ali Allana), a renowned Pakistani poet and writer.

He often explored themes of identity, spirituality, and existentialism in his poetry.