Name the oldest tree.

Name the oldest method of crop improvement.

Name three trees which are found in forests.

Name the group of the most primitive procaryotes which are regarded as the oldest of the living fossils.

Name the country that has the highest number of Ramsar trees?

Name the peripheral and water proof dead tissue of old stem of woody trees.

A tree stands vertically on the bank of a river. From a point on the other bank directly opposite the tree, the angle of elevation of the top of the tree is 60^@ . From a point 20 m behind this point on the same bank, the angle of elevation of the top of the tree is 30^@ . Find the height of the tree and the width of the river.