21.

Primary phloem develops from
A. lateral meristem B. protoderm
C. extrastelar cambium D. provascular tissue
Answer and Explanation
Answer:D
Explanation: No answer description available for this question.
22.

Other than spreading malaria, anopheles mosquitoes are also vectors of
A. dengue fever B. filariasis
C. encephalitis D. yellow fever
Answer and Explanation
Answer:B
Explanation: No answer description available for this question.
23.

Plants that grow in saline water are called
A. halophytes B. hydrophytes
C. mesophytes D. thallophytes
Answer and Explanation
Answer:A
Explanation: No answer description available for this question.
24.

Pyorrhoea is a disease of the
A. nose B. gums
C. heart D. lungs
Answer and Explanation
Answer:B
Explanation: Pyorrhoea, or periodontal disease, to give it a proper medical term, is a disease of the gums, it is one of the most widely prevalent diseases. It affects the membrane surrounding the roots of the teeth and leads to loosening of the teeth, pus formation, and shrinkage of the gum. This disease is the primary cause for tooth loss among adults.
25.

Placenta is the structure formed
A. by the union of foetal and uterine tissue B. by foetus only
C. by fusion of germ layers D. None of these
Answer and Explanation
Answer:A
Explanation: No answer description available for this question.