Question Library

The parts labelled are: I - IRIS II - EYE LASHES III - PUPIL IV - SCLERA The sclera, cornea, eyelids, eyelashes, and bony orbit all protect the eye from injury. Sclera - labelled IV The tough, white, fibrous tissue that surrounds the eyeball Helps maintain the eye's shape Protects the eye from injury Extends from the cornea to the optic nerve at the back of the eye Cornea The clear, curved layer in front of the iris and pupil Protects the front of the eye Helps focus light on the retina at the back of the eye Eyelids Thin flaps of skin and muscle that can cover the eye Reflexively close quickly (blink) to protect the eye from foreign objects, wind, dust, insects, and very bright light Eyelashes - labelled II Short, tough hairs that grow from the edge of the eyelid Keep insects and foreign particles away from the eye

In the light stage of photosynthesis, the key events include: chlorophyll absorbing light energy, excited electrons being transferred through electron transport chains, water splitting to release oxygen, and the generation of ATP and NADPH molecules using the captured energy from light; all of these processes occur within the thylakoid membranes of chloroplasts. However, Carbon(IV) oxide does not combine with hydrogen in the light stage.

Wilting occurs when a plant loses more water through transpiration than it absorbs from the soil.To prevent further water loss, the stomata on the leaves close. When the stomata are closed,CO\(_2\) can't enter the leaf. CO\(_2\) is essential for photosynthesis, which produces glucose and oxygen. The rate of photosynthesis decreases in a wilted herbaceous plant because the stomata close, preventing carbon dioxide (CO\(_2\)) from entering the leaf.

The elements needed for chlorophyll formation in plants are iron, magnesium, and nitrogen. Explanation Iron: Helps synthesize chlorophyll and maintains the structure of chloroplasts, which contain chlorophyll Magnesium: An essential component of chlorophyll, which is a vital pigment for photosynthesis Nitrogen: Helps plants produce chlorophyll Chlorophyll is a green pigment found in the chloroplasts of plants and algae. It's essential for photosynthesis, which is the process by which plants convert light energy, carbon dioxide, and water into sugar and oxygen.

Digestion in mammals breaks down food into nutrients that the body uses for energy, growth, and repair. How digestion works Ingestion: Food is taken in. Mastication: Food is chewed and mixed with saliva. Secretion: Digestive juices are released into the digestive tract. Digestion: Food is broken down into smaller molecules. Absorption: Nutrients, water, vitamins, and electrolytes are absorbed into the bloodstream. Evacuation: Waste products are eliminated.

Benedict's reagent is used to test for the presence of reducing sugars in a sample, like glucose, by changing colour from blue to green, yellow, orange, or red depending on the concentration of the sugar present; a positive result indicates the presence of a reducing sugar and is shown by a brick-red precipitate forming. Fructose, glucose and galactose are reducing sugar but sucrose is a non-reducing sugar.

The parts labelled are: I - Iris II - Eye lashes III - Pupil IV - Sclera

I - Self pollination II - Self pollination III - Cross pollination Self-pollination occurs when pollen grains are transferred from anther to the stigma within the same flower(as seen in I) or plant(as seen in II), while cross-pollination occurs when pollen grains are transferred from the anther of a plant to the stigma of another plant of the same species(as seen in III).

The condition necessary for reproduction to occur between plants P and Q after pollination is that plants P and Q must be of the same species.

The dehiscent fruit is the Tridax. The Tridax procumbens plant's seeds are dispersed by the wind because they have a pappus, which is a feathery appendage. The pappus's adhesion power allows the seeds to cling to the hairs of animals or clothing.

The parachute-like tuft of hairs found in Tridax develops from the calyx (modified sepals).

Sunlight is the primary source of light and heat on Earth. It's also a major source of energy, vitamin D, and contributes to climate and weather patterns.

Discouraging the use of poison to kill fish in a large water body is a way of conserving the fish species. Poisons can be used in water bodies to control fish populations, but they can also contaminate water and harm aquatic life.

The pathway through which nutrients are replenished and circulated in an ecosystem is called a biogeochemical cycle. Biogeochemical cycles are also known as nutrient cycles.They describe how chemical elements move through the atmosphere, soil, rocks, water, and organisms.

In a food chain, energy is transferred from one trophic level to the next, with each level typically having fewer individual than the previous ones.In a food chain, producers have more energy than primary consumers. Producers are the first level in a food chain, and they produce their own food using energy from the sun. Primary consumers are the next level up in the food chain, and they eat the producers.