Seminal plasma mainly consists of contributions from all the following except:
1. Testes
2. Seminal vesicles
3. Prostate
4. Bulbo-urethral glands

Which one of the following statements is false in respect of viability of mammalian sperm?
1. Viability of sperm is determined by its motility.
2. Sperms must be concentrated in a thick suspension.
3. Sperms are viable for only up to 24 hours.
4. Survival of sperm depends on the pH of the medium and is more active in alkaline medium.