Question

1. How exchange of gases takes place in plants?
2. Why transport in xylem is unidirectional and phloem is bidirectional?

3. Name the components of formed elements present in blood and mention the major function of each of

them?

Answer 1

1.exchange of gases in plants takes place through pores called stomata present in leaves
2.the xylem transports water in plants from the root to tip so it is unidirectional but in case of phloem it transports food in plants that is from the leaves to root or other parts of the plant body but in spring season it gets reversed as the food stored in the sink is mobilised towards the source therefore it is bidirectional
3.the major components of blood are :
a. Erythrocytes -these are the most abundant cells and carry red pigment known as haemoglobin. there are about 5-6 million rbcs in per cubic mm of blood.
b . leukocytes- these are colour less cells which do not contain haemoglobin and these are the largest cells of the body. these are about 5000-8000 NBSc per cubic mm of blood.
c . platelets - these are small irregular bodies present in blood. they contain essential chemicals that helps in blood clotting. there are about 1.5 to 2 lakh platelets in per cubic mm of blood
hope ur satisfied with the answer