Question

(a) It allows the entry of selective substance
(b) It does not allow entry of any substance
(c) It allows the exist of selective substances
(d) It allows entry only.
(i) It does not allow entry of any substance and allows
the exit of selective substances are correct.
(ii) All of these.
(iii) It allows the entry of selective substances, it allows
the exit of selective substances are correct.
(iv) It allows the entry of selective substances, it does not
allows entry of any substances and it allows the exist
of selective substances are correct.​

Answer 1

Answer:

what is the meaning of the question