How many statements are wrong for contraceptives?

(i) Natural methods works on the principle of avoiding chances of ovum and sperms meeting.

(ii) Ovum and sperms are prevented from physically meeting with the help of saheli pill.

(iii) IUDs increase phagocytosis of sperms within the uterus.

(iv) IUDs, make the uterus unsuitable for implantation and the cervix hostile to the sperms.

(v) Oral contraceptive pills alter the quality of cervical mucus to prevent/ retard entry of sperms.

(vi) Sterilization prevents conception.