(A) The Amazon rainforest being cut and cleared for cultivation of soyabeans is an example of habitat loss. (B) Steller's sea cow and passenger pigeon became extinct due to over-exploitation by humans. (C) The Nile perch introduced into Lake Victoria in East Africa helped in population growth of cichlid fish in the lake. (D) Water hyacinth is an invasive species. (E) When a species becomes extinct, the plant and animal species associated with it are not affected.
Choose the correct answer from the options given below:
Amazon deforestation is habitat loss. Steller's sea cow and passenger pigeon became extinct due to over-exploitation. Nile perch caused decline of cichlid fishes. Water hyacinth is an invasive alien species. Extinction may lead to co-extinctions.
Which one of the following disorders is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule?
Sickle-cell anaemia results from a point mutation in the ฮฒ-globin gene causing substitution of glutamic acid by valine at the sixth position.
Find the incorrect statement(s) about photosynthesis from the following:
(A) The water splitting complex is associated with PS I. (B) C4 plants use the C3 pathway of CO2 fixation as the main biosynthetic pathway. (C) In C4 plants, photorespiration does not occur. (D) C3 plants exhibit Kranz anatomy. (E) ATP synthesis in chloroplast occurs through chemiosmosis.
Choose the correct answer from the options given below:
Water splitting occurs in PS II, not PS I. Kranz anatomy is a feature of Cโ plants, not Cโ plants. Statements B, C and E are correct.
Identify the correct statements about biomolecules.
(A) Lipids are generally water soluble. (B) Proteins are polypeptides. (C) Polysaccharides are long chains of sugars. (D) Adenine and guanine are substituted pyrimidines. (E) Almost all enzymes are proteins.
Choose the correct answer from the options given below:
Lipids are generally insoluble in water. Adenine and guanine are purines, not pyrimidines. Proteins are polypeptides, polysaccharides are polymers of sugars, and almost all enzymes are proteins.
Incomplete dominance is seen in Antirrhinum, co-dominance in ABO blood groups, pleiotropy in phenylketonuria and polygenic inheritance in human skin colour.