15] Select the correct answers to the questions from the given options. (Do not copy the questions, write the correct answer only).
Assertion(A): Arachnoid layer helps in speeding up the transmission of nerve impulses along the axons.
Reason(R): Axon endings at the synapse secrete acetylene.

15] Select the correct answers to the questions from the given options. (Do not copy the questions, write the correct answer only).
The structure that lies at the junction of the choroid and the iris and is itself a part of the choroid is called:

15] Select the correct answers to the questions from the given options. (Do not copy the questions, write the correct answer only).
The optimum temperature for photosynthesis is:

Given below is a picture of a tree. Mention the scientific phenomena occurring in the parts labelled (a),
(b) and (c).
(c)
(b)
(a)

15] Select the correct answers to the questions from the given options. (Do not copy the questions, write the correct answer only).
The number of live births per thousand people per year is called:

What are biomedical wastes? Give an example.

State any two harmful effects of acid rain.