Not every coitus leads to pregnancy and fertilisation Give reasons - Biology - Human Reproduction

Question

Not every coitus leads to pregnancy and fertilisation Give
reasons

Kali Prasad · Accepted Answer

For Fertilisation to occur,the egg from ovary releases into the
fallopian tube and reaches to the ampullary-ishthmic junction of
the fallopian tube and wait for the sperm to come The egg survives
for only 24 hours so,if a sperm come in contact with the egg in
this duration then fertilisation will ocur and leads to pregnancy
later but this does not happen each time you can understand why

Not every coitus leads to pregnancy and fertilisation.Give reasons