What are nastic and curvature movements? Give one example of each.

(a) What is reflex action? Give its two examples. Illustrate the pathway followed by a message from the receptor in a reflex arc. (b) Name the actions of sympathetic and parasympathetic systems on eye.

Updated 1/19/2026

(a) Write foil form of DNA. (b) Why are variations essential for the species ? (CCE 2011)

Updated 1/19/2026

For two statements are given- one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below: a. Both A and R are true, and R is correct explanation of the assertion. b. Both A and R are true, but R is not the correct explanation of the assertion. c. A is true but R is false. d. A is false but R is true. Assertion: A child which has inherited X chromosome from father will develop into a girl child. Reason: Girl child inherits X chromosome from father and Y chromosome from mother.

Updated 1/19/2026

Define (a) Biomass (b) Anaerobic degradation.

Updated 1/19/2026

(b) What is • Phototropism and • Geotropism? With labelled diagrams describe an activity to show that light and gravity change the direction that plant parts grow in. (b) Mention the role of each of the following plant hormones: • Auxin • Abscisic acid.

Updated 1/19/2026