Atomic mass unit is the standard unit that is used for indicating mass on an atomic or molecular scale
Everything is made of atoms. An atom is the smallest particle of an element, like oxygen or hydrogen. Atoms join together to form molecules. A water molecule has three atoms: two hydrogen (H) atoms and one oxygen (O) atom.
Answer:
Tyre
In cold weather, you might have regularly kept a check on the pressure of the tyres of your car. Driving increases the temperature of the tyres, and, therefore, the air inside the tyre warms and expands. When you measure the pressure of the tyres at the time when you have just driven the car, it will be high. However, in cold weather, the pressure of the tyres will be low. So, it is recommended that you should always measure the pressure of the tyres.
Answer: a) 
b) 
c) 
d) 
Explanation:
General representation of an element is given as:_Z^A\textrm{X}
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
Mass number is defined as the sum of number of protons and neutrons that are present in an atom.
Mass number = Number of protons + Number of neutrons
In an atom, when neutrons or protons are lost or gains, it directly affects the mass number of an atom.
Atomic number is defined as the number of protons or number of electrons that are present in an atom.
It is characteristic of a particular element.
Atomic number = Number of electrons = Number of proton
a) Z 74, A 186: 
b) Z 80, A 201: 
c) Z 34, A 76: 
d) Z 94, A 239.: 
B, they then interpret that data to find their answers