Explanation

(a)Succession can be defined as a progressive natural development of vegetation towards a climax during which one community is gradually replaced by others. The abandoned farm land is a secondary succession as a result of the fact that it follows a partial destruction of the original vegetation.

The process is as follows:

(i) Decay of plants and animals of the old farm enhances nutrient of the soil.

(ii) The pioneer or initial colonizers are insects' eggs, larvae, worms and seeds of plants carried by animals or by wind. There are also underground stems like rhizomes and stem tubers.

(iii) Next stage includes the hatching of eggs of insects, larvae development, germination and growth of herbaceous plants like grasses and lilies.

(iv) Growth of vegetation attracts rodents to feed on grasses.

(v) Lizards are also attracted to feed on the insects.

(vi) Herbs are displaced by shrubs.

(vii) Shrubs are in turn displaced by trees.

(viii) Trees attract birds, monkeys and tree reptiles.

(ix) Presence of herbivores, carnivores and omnivores (animal community) makes the community to develop or reach a climax. This results in a complex food web.

(b) Ways by which micro-organism can be controlled to maintain good health are:

(i) People should be vaccinated against killer diseases.

(ii) There should be personal hygiene, e.g. regular cleanliness of our body, environment, teeth and clothes.

(iii) Avoid overcrowding to prevent infectious diseases, e.g. tuberculosis.

(iv) Destroy breeding ground for mosquitoes.

(v) Isolate people with highly infectious diseases, e.g. leprosy

(vi) Promote health education

(vii) Cover food to prevent contamination by rats, flies, cockroaches, etc.

(viii) Encourage ventilation of houses.

(ix) Cut bushes around the house and drain stagnant water properly.

Correct Answer: B. Proteins

Explanation

By process of elimination, lipids and fats cannot be the correct answer-they are synonymous (lipids are also known as fats). Carbohydrates, eg sugars and starches are composed only of carbon, hydrogen, and oxygen. Nucleic acids contribute to DNA and RNA structure and function. The correct answer is proteins, made of long chains of amino acids-amino acids are sometimes called the building blocks of proteins.

Correct Answer: D) cytoplasmic membrane

Explanation

This question is asking which of the given options is essential for a living cell. The options are flagella, capsule, cell wall, cytoplasmic membrane, and capsule and cell wall. Flagella are long whip-like structures that some cells use for movement. While flagella are important for some cells, they are not essential for all living cells. Therefore, option A is not the correct answer. A capsule is a protective layer that surrounds some bacterial cells. It helps the cell to avoid being engulfed by white blood cells and to adhere to surfaces. However, not all living cells have a capsule, so option B is also incorrect. The cell wall is a structure that surrounds the cell membrane and provides support and protection to the cell. While the cell wall is important for many cells, not all living cells have a cell wall. Therefore, option C is not the correct answer. The cytoplasmic membrane, also known as the cell membrane, is a thin layer that surrounds the cell and separates the interior from the exterior. It controls the movement of substances in and out of the cell and is essential for all living cells. Therefore, option D is the correct answer. Option E states that both capsule and cell wall are essential for a living cell. However, this is not true as not all cells have a capsule or a cell wall. Therefore, option E is incorrect. In conclusion, the essential structure for a living cell is the cytoplasmic membrane or the cell membrane. This structure is present in all living cells and is responsible for controlling the movement of substances in and out of the cell.

Correct Answer: C. kidney

Correct Answer: B. Carolus Linnaeus

Correct Answer: D. Allele

Correct Answer: D) Shark

Explanation

This question is asking which of the animals listed is not metamerically segmented. Metamerically segmented means that the animal's body is divided into repeating segments. Option A, the tapeworm, is a type of flatworm that is not segmented. However, it is important to note that tapeworms do have a head and tail region. Option B, the earthworm, is an annelid worm that is metamerically segmented. Each segment of its body contains muscle, nerve, and excretory systems. Option C, the centipede, is also metamerically segmented. Each segment contains a pair of legs. Option D, the shark, is not metamerically segmented. Its body is divided into several regions such as the head, trunk, and tail, but it does not have repeating segments like the earthworm or centipede. Therefore, the correct answer is Option D, the shark. It is important to understand the concept of metamerically segmented animals as it is a fundamental concept in Biology.

Correct Answer: C. DNA analysis

Correct Answer: D. The operon is usually off and has an active repressor

Explanation

With an inducible system, the operon is off, meaning its repressor is active, or actively repressing the system from turning on. Inducible operons are opposite to a repressible operon, which is always on until it is repressed.

Correct Answer: A. Well differentiated sepals and petals