Correct Answer: D. isotonic sugar solution

Correct Answer: D) to stop chemical reactions

Explanation

When testing a leaf for starch, it is first placed in boiling water to stop chemical reactions that may interfere with the test. When the leaf is boiled, it denatures the enzymes that are responsible for breaking down starch. This prevents the breakdown of starch and ensures that we can accurately test for the presence of starch in the leaf. Boiling water does not extract chlorophyll or remove colour from the leaf. It may dissolve some of the pigments in the leaf, but this is not the main reason for boiling the leaf. Although boiling water can dissolve starch, this is not the reason why the leaf is boiled. In fact, boiling water can cause the starch granules to burst, which can lead to inaccurate results. Therefore, the correct option is D - to stop chemical reactions that may interfere with the test. It is important to note that the test for starch involves using iodine solution, which reacts with starch to produce a blue-black color. Overall, boiling the leaf before testing for starch is a crucial step in ensuring accurate results. This helps to prevent interference from enzymes and other chemical reactions that may affect the outcome of the test.

Correct Answer: C. Chloroplast

Correct Answer: A. secondary consumers to decomposers

Correct Answer: A. referencing purposes

Correct Answer: D. Nuclear envelope

Explanation

The nuclear envelope separates transcription from translation in a eukaryotic cell. Translation cannot occur until transcription is finished, which is the opposite of what occurs in a prokaryotic cell. In eukaryotic cells, transcription occurs in the nucleus where mRNA will be produced. Once mRNA is produced, it will exit the nucleus through pores and then proceed to be translated into protein in the cytoplasm.

Correct Answer: A. uric acid

Explanation

a [i]Ecological niche

where and organism lives and the role it plays in an ecosystem/community.

[ii] Roles of a mango tree in its ecological niche

i. absorbs water/mineral salts from the soil organism normally lives; and the

ii.absorbs sunlight for photosynthesis

ii.provides shelter for animals/other plants

IV.acts as support for creepers

V. produces fruits/food/serves as food

Vi. serves as fuel source for animals vii. covers the ground with dead leaves that enrich the soil

b[ i] Counting individuals could be impossible/difficult in fast moving animals

ii. Counting individuals could be tedious ii. Counting individuals could be time consuming/use of technique saves time

iv. The terrian/habitat could be difficult to reach

[ii] i. Quadrat method ii Random sampling method

ii.Sweep net method iv cluster sampling

V. Pitfall trap method vi. Line transect method

Vili.Light trap method ix. Stratified sampling

X. Tullgren funnel method xi. Convenience sampling

xii systematic sampling method

[c]i .Arch/tented arch ii compound

iii loops/double/central pocket/ulna radial loop

iv.whorls/accident/plain whorl

[d]i Pea plant/Garden pea plant/Pisum sativum.

ii a it is self-pollinated/flowers are bisexual

b has short life cycle

c produces many offspring in one cross

d presence of distinct physical characters that are easily recognisable.

b.Has a short life cycle

c.produces many offspring in one cross

d.presence of distinct physical characters that are easily recognisable

Correct Answer: D. Frog

Correct Answer: D) cerebrum

Explanation

The question is asking which part of the mammalian brain is responsible for deciding whether to run or walk. The options given are cerebellum, medullar oblongata, midbrain, and cerebrum. The correct answer is the cerebrum. The cerebrum is the largest part of the mammalian brain and is divided into two hemispheres. It is responsible for conscious thought, decision-making, and voluntary movement. The cerebrum is also involved in sensory perception, memory, and emotion. In contrast, the cerebellum is responsible for coordinating movement and balance, while the medullar oblongata controls vital functions such as breathing and heartbeat. The midbrain is involved in auditory and visual processing, as well as motor control. Therefore, when an individual needs to make a conscious decision to run rather than walk, it is the cerebrum that is responsible for such a decision. It analyzes the sensory input from the environment and makes a decision based on past experiences and current circumstances. In conclusion, the correct answer to the question is the cerebrum. It is responsible for conscious thought, decision-making, and voluntary movement, including the decision to run rather than walk.