Correct Answer: B. stamen

Correct Answer: B. red colour was dominant

Correct Answer: B. Mosquito transmitting malaria

Explanation

A disease vector is an organism that transmits disease-causing pathogens from one host to another. Female Anopheles mosquitoes can carry and transmit the Plasmodium parasite, which causes malaria. When an infected mosquito bites a person, it injects the parasite into the bloodstream, leading to the transmission of the disease.

Correct Answer: D. the body is covered by chitin

Correct Answer: C. pollination

Correct Answer: B. Mineral deposit

Correct Answer: C. hepatic portal vein

Explanation

(a) Difference between tropic movement and nastic movement

(b) How light brings about tropic movement in stem and root of a flowering plant:

(i) When unilateral light falls on the stem, the auxin/growth hormone/IAA is displaced from the lighted to the dark side.

(ii) The increase in auxin concentration on the dark side increases growth on that side causing the stem to bend towards the light/positive phototropism.

Roots:

(i) The auxin is displaced from the lighted side to the dark side.

(ii) The increase in auxin concentration retards growth on the dark side causing the root to bend away from the light/negative phototropism.

(c) The following would be observed when a growing seedling is placed horizontally:

(i) Shoot bends upwards, showing negative geotropism/positive phototropism.

(ii) Root bends downwards, showing positive geotropism/negative phototropism.

(d) Functions of the Pituitary gland:

(i) Stimulates growth/growth of long bones/cell division.

(ii) Stimulates production of sex-hormones/named sex hormones.

(iii) Stimulates production of anti-diuretic hormone/ADH/regulation of water re-absorption in the kidney/osmos regulation.

(iv) Produces hormones which control other endocrine glands/stimulates thyroid gland/adrenal cortex.

(v) Stimulates protein synthesis.

(vi) Induces birth by contraction of uterine muscles/production of oxytoxin.

(vii) Induces milk secretion/produces prolactin.

(viii) Controls egg and sperm production.

(e) Differences between growth in plants and animals:

Correct Answer: C. Urea

Correct Answer: D) always affects the chromosome number

Explanation

This Biology question is asking which of the following statements is not true about gene mutation. The options are A, B, C, and D. Option A states that gene mutation introduces new traits into a population. This is true. Gene mutation can introduce new traits into a population, which can lead to genetic diversity. Option B states that gene mutation causes changes in the DNA. This is also true. Gene mutation can cause changes in the DNA sequence, leading to changes in the protein that is produced. Option C states that gene mutation is a source of new genes. This is also true. Gene mutation can create new genes, which can lead to new traits in a population. Option D states that gene mutation always affects the chromosome number. This is not true. Gene mutation can affect the DNA sequence without affecting the chromosome number. Therefore, option D is the correct answer. It is important to note that gene mutation can have both positive and negative effects. Some mutations can be beneficial, while others can be harmful. Mutations can also be inherited or acquired during an organism's lifetime. In summary, the correct answer to this Biology question is option D, as gene mutation does not always affect the chromosome number.