Evolution — BIOLOGY STD 12 Science — Question

Why do the sons of a haemophilic father never suffer from this trait?

If the stamens are well exposed, usually which mode of pollination the plant is expected to follow?

The backbone of DNA strands contains atoms joined by covalent bonds, whereas the bases between the two strands are hydrogen bonded. Based upon your knowledge of bonds, what is the significance of the type of bonding existing in a DNA molecule?

Certain molecular processes are given in column (A). Provide the terms given to these processes in column (B), after selecting them from the terms:
Recombination, gene regulation, prokaryotic transcription, eukaryotic transcription, translation, replication, gene transfer, DNA fingerprinting

S.No.	Column A	Column B
(i)	DNA → DNA
(ii)	DNA → hRNA
(iii)	mRNA → Protein
(iv)	Repressor Protein + Operator → No transcription

From where the parturition signals arise-mother or foetus? Mention the main hormone involved in parturition.

Is it possible to achieve ‘zero population growth rate’? If yes, what kind of age pyramid is obtained?

Lung cancer, Pituitary, Spleen, Skin cancer, Cancer of adipose tissue, lymph nodes, Adrenal, Bone tumour.

Column (A Type of cancer)	Column B (Organs affected)
(1) Carcinoma	————–
(2) Sarcoma	————–
(3) Lymphoma	————–
(4) Adenocarcinoma	————–

Have you heard of modern synthetic theory of evolution. What are the drawbacks of mutation theory that could lead to formation of a new theory?

Give reasons : The vestibule of nasal chamber has fine hair.