2. All human beings have pairs of chromosomes in the nuclei of their cells :

3. The unfertilized egg always has......... x chromosome:

4.' Goiter ' is a disease of:

5. Adrenalin hormones is produced by:

6. when the sperm contribute a Y- chromosome of the egg (ovum) at fertilization than the zygote would develop into a:

7.which gland secretes insulin ?

8. which of the following controls sugar in blood ??

9.the change from larvae to adult is called