Why does lack of oxygen in muscles often lead to cramps among cricketers? Answer - This happens due to the conversion of pyruvate to...

Which is the first enzyme to mix with food in the digestive system? Answer - Salivary amylase

Which part of root is involved in the exchange of respiratory gases in plants? Answer - Root hairs are involved in the exchange of...

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

What is the main function of kidneys in humans? Answer - Kidneys excrete water and dissolve metabolic wastes, e.g., urea and other...

What will happen if platelets were absent in the blood? Answer - In the absence of platelets, the process of clotting will be affected.

What will happen to a plant if its xylem is removed? [CBSE Delhi 2009] Answer - The xylem tissue transports water and minerals from the...

Define photolysis. Answer - The phenomenon of breaking down of water molecule using solar energy absorbed by chlorophyll molecules is...

Why is energy required by an organism even during sleep? Answer - This is because even when an organism is asleep, various biological...

How it can be proved that the basic structure of the Modern Periodic Table is based on the electronic configuration of atoms of different...

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

Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order? Give reason. Answer - Noble...

Identify and name the metals out of the following elements whose electronic configurations are given below. (i) 2, 8, 2 (ii) 2, 8, 1...

What is atomic radius? Why does atomic radius decrease across a period? Answer – Atomic radius is defined as the distance from the center...

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

What do you understand by the term periodicity? Does the periodicity in properties is a function of valence electrons? Illustrate. Answer...

Name the element which is in (i) First group and third period (ii) Seventeenth group and second period. Answer - (i) Sodium (ii) Fluorine

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

If an element X is placed in group 14, what will be the formula and the nature of bonding of its chloride? [CBSE 2019] Answer - The...

Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev. Answer – GeCl4, GaCl3