Correct Answer: B. Man would occupy the apex of the web

Explanation

(i) Effect of gravity on plant growth: The (main) root grows down in response to gravity/positively geotropic; the (main) stem/shoot/grows upwards away from gravity/negatively geotropic.

(ii) Experiment to demonstrate the effect of gravity on the roots of a plant: -

• Select three germinating bean seedlings/seeds on a moist/damp sawdust/wet blotting paper
• Pin/keep one seedling in a horizontal position
• Place another seedling in a vertical position with the radicle pointing upwards
• Place the third upwards vertical with the radicle pointing downwards, to serve as control
• After few/2-3 days, it will be observed that the radicle of the seedling placed horizontally bends/ grows downwards
• the radicle of seedling placed vertically bends/grows downwards
• Indicating positive geotropism/ positive response to gravity.
• The seedling placed vertically with radicle point downwards did not bend. (N.B. observation must correspond with the experimental procedure to score).

ALTERNATIVE to 1 (a)

• (ii) Take a clinostat and two bean seedlings
• Pin one seedling horizontally on damp/moist/wet/cotton wool/blotting paper attached to the cork of the clinostat
• Pin the other seedling onto some damp/moist/wet cotton wool/blotting paper attached to the cotton tile
• Start the motor of the clinostat; Observe the seedlings after 8 —10 hrs.
• It will be observed that the radical of the seedling placed horizontally bends/grows down wards
• Indicating/showing positive geotropism.

(b) Detection of bitter taste in humans

• Taste buds are unevenly distributed on the surface of the tongue
• Taste buds for detecting bitterness are at the back/end of the tongue
• For a substance to be tasted it must be dissolved in a solution/saliva
• When bitter substance is dissolved in saliva, sensory cells at end/back of the tongue are stimulated
• Which pass impulses to the brain; Which interprets the taste as bitter.

(c) Hormones of endocrine glands and their functions

Correct Answer: A) a community

Explanation

Ecology is the study of living things and their environment. In this question, we are asked about the Ecology of an abandoned farmland. An abandoned farmland is an example of a habitat, which is a place where living things live. Ecology can be studied at different levels, such as an individual, a population, a community, or an ecosystem. A population refers to a group of individuals of the same species living in the same area, while a community refers to all the populations of different species living in the same area. An ecosystem refers to the interactions between living things and their environment, including non-living things such as water and soil. Therefore, the correct answer to this question is Option A: a community. This is because we are interested in the interactions between different populations of living things in the abandoned farmland, which is an example of a community. Option B (a population) and Option C (a species) are incorrect because they only refer to one type of living thing in the area. Option D (an ecosystem) is incorrect because it includes non-living things in addition to living things. It is important to study Ecology because it helps us understand how living things interact with each other and their environment. This knowledge can be used to manage and conserve natural resources, and to address environmental problems such as pollution and climate change.

Correct Answer: C. renal vein

Correct Answer: A. stomata and lenticels

Correct Answer: D. codon

Explanation

The three base grouping in RNA that determines the amino acid created in translation is known as a codon. Gene refers to the region on DNA that codes for a given trait. Operators and promoters are also located on DNA, and act as regulatory elements.

Correct Answer: D. Gets rid of excess water

Correct Answer: C. becomes the fruit

Correct Answer: B. Bryophylum

Correct Answer: D) Tracheal tubes

Explanation

A grasshopper is an insect that needs oxygen to survive. Respiration is the process by which living organisms obtain oxygen and release carbon dioxide. The question is asking how a grasshopper breathes, specifically, what organ or structure it uses to respire. The options provided are lung-books, gills, lungs, and tracheal tubes. Lung-books and gills are not correct because these organs are not found in grasshoppers. Lungs are also not correct because grasshoppers do not have lungs like mammals do. The correct answer is tracheal tubes. Tracheal tubes are a network of tubes that run throughout the body of an insect and allow oxygen to diffuse directly into the cells. These tubes are like a series of tiny straws that allow air to enter the body and reach the tissues. Insects have a system of valves and spiracles (tiny openings) that regulate the flow of air in and out of the tracheal tubes. In summary, grasshoppers respire by using tracheal tubes. These tubes are a network of tiny tubes that allow oxygen to enter the body and reach the cells. They are not lungs or gills.