Energy can be conserved by efficient energy use.
Answer: Option A
<u>Explanation:</u>
Energy can be transferred from one form to another, but it cannot be destroyed or created. So it can be conserved if efficiently used. Thus efficient usage of energy lead to conservation of energy. Due to conservation of energy, the forces can be renewable and non-renewable.
So, we should know how the input energy can be completely converted to another form of energy leading to efficient usage of energy without any loss. As if there is no loss, input energy will be equal to output energy leading to 100% efficiency.
A scientific theory focuses on explaining a phenomenon, while a law will have a generalised statement about said phenomenon. Often times, we use laws to help us develop theories. =)
Global Warming has been increased by living organisms like animals and humans by many ways:
1) We burn fossil fuels, which is very bad for our Environment's health
2) Animals like cows & buffalo produces a lot of methane which causes Global Warming.
3) Animals cut a lot of trees for their products, so increase the amount of Carbon dioxide in the atmosphere, thus increases Global Warming.
4) We don't minimize our dependence on Non-renewable source of energy which 'causes a lot of pollution in the environment
Hope this helps!
Prediction, control and experiment
Answer:
Oxidizing element: Mg
Explanation:
Reaction of magnesium and oxygen can be written as:
while writting chemical reaction between two atom or element then write their natural form i.e. how that atom or element exist in the nature.
eg. reaction of any element with Oxygen atom then we can not write directly O because oxygen exist in the nature in form of 
finding oxidation number each side:
Reactant side:
Mg=0;
O=0;
product side:
Mg=+2;
O=-2;
from above:
oxidation number of Mg is increasing hence this is oxidizing element
