Answer:
80%
Explanation:

800 / 1000 = 0.8
Efficiency = 0.8 *100 = 80%
Engineers have designed experimental cars that use liquid hydrogen for fuel instead of gasoline. this is an example of Substitution.
Substitution is the process where one thing replaces other for a particular purpose. here liquid hydrogen is replacing the gasoline for fuel in car. hence the correct word to fill is Substitution.
Answer:
No
Explanation:
Crystizaltion of magma turns into indeginous rocks which then turns into sediment after weathering and erosion.
the answer is A it is so easy question