Down's syndrome is caused due to

• monosomy of 21st chromosome

• trisomy of 21st chromosome

• an extra chromosome in male

• an extra chromosome in female

Scurvy is caused due to deficiency of

• vitamin D

• vitamin K

• vitamin C

• vitamin A

Silk is obtained from which stage of silkworm?

• Egg

• Pupa

• Adult

• Larva

Vivipary germinations are found in

• Aquatic plants

• Xerophyte plants

• Mangrove plants

• Shrubs

Which one is a weak acid?

• Citric acid

• Nitric acid

• Sulphuric acid

• Hydrochloric acid

Magnetic quantum number determines

• shape of orbitals

• orientation of orbitals

• total energy of an-orbital

• spin of an electron

Which scientist was developed the 'key' for the identification of animals?

• Goethe

• Cuvier

• John Ray

• Theophrastus

HIV mainly infects

• Cytotoxic T-lymphocytes

• Helper lymphocytes

• Killer lymphocytes

• Cell mediated T-lymphocytes

Fibers of cotton are obtained from

• the inner fruit wall

• calyx

• seed coat

• fruit wall

Seedless fruits are of no use in

• Coconut

• Tomato

• Banana

• Grape