Physical changes occur when objects or substances undergo a change that does not change their chemical composition. This contrasts with the concept of chemical change in which the composition of a substance changes or one or more substances combine or break up to form new substances.
Answer:
The correct answer is option A.
Explanation:
Equilibrium is a state when rate of forward reaction is equal to the rate of backward reaction. The concentration of reactants and products becomes constant at this state.
The ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric coefficients is termed as Equilibrium constant. It is denoted by 
.
aA + bB 
cC
![K_{eq}=\frac{[C]^c}{[A]^a[B]^b}](https://tex.z-dn.net/?f=K_%7Beq%7D%3D%5Cfrac%7B%5BC%5D%5Ec%7D%7B%5BA%5D%5Ea%5BB%5D%5Eb%7D)
Hey! 1) Convection [Warm water is less dense, so it rises.] 2) Conduction [The metal skewer is heated by the fire, and it is directly touching your hand. The metal skewer transfers heat to your hand through conduction.] 3) Conduction [The rock is directly touching you, so it transfers heat to you through conduction.] 4) Convection [Convection causes weather systems because hot air sinks and cold air sinks] 5) Convection [The hot air rises because it is less dense while the cold air sinks because it is denser.] ~Hope this helped~
Calcium is stored in bones in the body
element is made up of only one type of atoms.
it is pure form of matter
example hydrogen, oxygen, carbon etc
