Why does lack of oxygen in muscles often lead to cramps among cricketers?

Which is the first enzyme to mix with food in the digestive system?

Which part of root is involved in the exchange of respiratory gases in plants?

Why do the walls of trachea not collapse when there is less air in it?

What is the main function of kidneys in humans?

What will happen if platelets were absent in the blood?

What will happen to a plant if its xylem is removed? [CBSE Delhi 2009]

Define photolysis.

Why is energy required by an organism even during sleep?

How it can be proved that the basic structure of the Modern Periodic Table is based on the electroni

Choose from the following. 6C, 8O, 10Ne, 11Na, 14Si (i) Elements that should be in the same period.

Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the origina

Identify and name the metals out of the following elements whose electronic configurations are given

What is atomic radius? Why does atomic radius decrease across a period?

Give reasons: (i) The elements of group 18 are called zero valent. (ii) Group 17 elements form unine

What do you understand by the term periodicity? Does the periodicity in properties is a function of

Name the element which is in (i) First group and third period (ii) Seventeenth group and second peri

Arrange the following elements in the increasing order of their metallic character Mg, Ca, K

If an element X is placed in group 14, what will be the formula and the nature of bonding of its chl

Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendelee