How is the entry of only one sperm and not many ensured into an ovum during fertilisation in humans?
During fertilisation, a sperm comes in contact with the zona pellucida layer of the ovum and with the help of acrosomal secretions induces changes in the membrane that block the entry of additional sperms. Thus, it ensures that only one sperm can fertilise an ovum
Name the respective pattern of inheritance where F1 phenotype
(a) does not resemble either of the two parents and is in between the two.
(b) resembles only one of the two parents.
Given reasons for the following:
(a) The human testes are located outside the abdominal cavity.
(b) Some organisms like honey-bees are called parthenogenetic animals.
Write the name of the following:
(a) The most common species of bees suitable for apiculture
(b) An improved breed of chicken
(a) Where do the signals for parturition originate from in humans?
(b) Why is it important to feed the newborn babies on colostrums?
