Chemistry
The three elements most needed in common fertilisers are :

Calcium, Phosphorous and Potassium
Nitrogen, Potassium and Phosphorous
Sulphur, Phosphorous and Sodium
Phosphorous, Sodium and Nitrogen

ANSWER DOWNLOAD EXAMIANS APP

Chemistry
The mass number of a nucleus is

always more than the atomic weight
the sum of the number of protons and neutrons present in the nucleus
always less than its atomic number
a fraction

ANSWER DOWNLOAD EXAMIANS APP