Correct Answer: B. crop rotation and cover crops

Correct Answer: A. vascular bundles

Correct Answer: D. Cellular differentiation leads to internal structural specialization

Explanation

(a). Characteristic of Enzymes;

• They are biological catalystsialter/speed up the rate of biological reactions
• remain chemically unchanged at the end of a reaction
• their actions are reversible
• they are specific in action/act on specific substrates
• enzymes are required in small amount
• are protein in nature
• they act best at optimum temperature/high temperature/denatures them/ low temperature inactivates them
• specific/sensitive to pH
• actions retarded by poisons/inhibitors
• some required co-enzymes to function.

(b)i. Digestive enzymes produced in the duodenum of humans

• Amylase
• Trypsin/chymotrypsin
• Lipase

ii. Substrates for each enzyme

• Amylase = starch
• Trypsin/chymotrypsin =protein
• Lipase = fats and oil

iii. Product of enzyme activity

• Amylase = maltose
• Trypsin/chymotrypsin = peptones/polypeptides/peptide
• Lipase =glycerol and fatty acid

(c)i. Importance of chlorophyll in plants

Absorbs/traps sunlight; for photosynthesis

ii. Macro-elements required for the formation of chlorophyll

• Nitrogen
• Magnesium
• Iron

iii. Deficiency symptoms of each macro-element in (c)ii

Nitrogen

• Chlorosis/yellowing of leaves
• Stunted growth
• Poor flower/fruit development

MagnesiuM

• Poor growth
• Chlorosis/yellowing of leaves

Iron

• Poor/stunted growth
• Chlorosis/yellowing of leaves

(d) Procedure for test for starch

• Detach/pluck off/take leaf to be tested from plant after 4 to 6 hours of exposure to sun to enable it to form starch
• Put leaf in boiling water for about 30 seconds to kill the cells
• Put boiled leaf in 70% warm alcohol/ethylated spirit in water bath to decolorise the leaf Rinse decolorised/brittle leaf in running cold water to soften the leaf tissues/remove alcohol
• Spread out on white tiles/watch glass and add a few drops of iodine solution
• Allow to stand for a few minutes
• It turns blue-balck showing/indicating presence of starch.

Correct Answer: B. Hugo de Vries

Correct Answer: A) the level of blood sugar would increase

Explanation

When a man's pancreas has been surgically removed, it means that the organ responsible for producing insulin and other important hormones has been taken out. As a result, the correct option is A, the level of blood sugar would increase. The pancreas produces insulin, which helps regulate the level of glucose (sugar) in the blood. Without the pancreas, the body cannot produce insulin, which would cause the level of glucose in the blood to rise. This is because the glucose cannot be transported from the bloodstream into the cells, where it is needed for energy. Option B, the glycogen content of the liver would increase, is incorrect. Glycogen is a storage form of glucose in the liver and muscles. However, the removal of the pancreas would not cause an increase in the glycogen content of the liver. Option C, his blood pressure would decrease, is also incorrect. The pancreas is not directly involved in regulating blood pressure. Option D, his weight would increase appreciably, is also incorrect. While the removal of the pancreas can cause weight loss, it is not likely to result in a significant increase in weight. In summary, the correct answer is option A, the level of blood sugar would increase, due to the absence of insulin production by the pancreas.

Correct Answer: A. Yellow fever

Correct Answer: B. suspends all cell organelles

Explanation

(a) The principal sense organs in mammals are:

(i) The eyes for seeing or viewing

(ii) The nose olfactory organ for smell or smelling

(iii) Ear for hearing, balancing and sense of position

(iv) Tongue for taste using the taste bud (bitter, sour and sweet tastes)

(v) Skin for touch, detection of temperature, pressure, pain, heat and cold.

(b)(i) This type of defect is known as long sightedness (hypermetropia). inability to focus near objects clearly but can see distant objects clearly. It is as a result of short eyeball, or the lens and ciliary muscles which has lost their elasticity, Light rays from near objects are normally focused behind the retina

(ii) The defect can be corrected by using a convex lens which coverages the light rays entering the eye to focus on the retina. Long sight is corrected by convex lens. The convex lens shorten the focal length, converge rays of light entering the eye from near object to focus on the retina.

Correct Answer: A) Cactus

Explanation

The question is asking which plant can survive in very dry conditions. The options are: A) Cactus, B) Raphia palm, C) Triplochiton scleroxylon, and D) Parkie biglobosa. The correct answer is A) Cactus. Cactus plants have adapted to their environment and can survive in extremely dry conditions because they store water in their thick stems. This allows them to survive long periods of drought. Cacti are native to arid regions of North and South America. They have evolved to survive in these harsh environments by developing specialized structures such as spines instead of leaves to reduce water loss through transpiration. While other plants may also have adaptations that allow them to survive in dry environments, the cactus is particularly well-suited to these conditions. For example, Raphia palm is a tropical plant that thrives in wet conditions, Triplochiton scleroxylon is a tree that grows in moist forests, and Parkie biglobosa is a deciduous tree that grows in savannas and woodlands. In summary, the plant that can withstand extreme dryness is the cactus because it has adapted to store water in its thick stem and has other specialized structures that reduce water loss.