Answer : The balanced chemical reaction will be:

Explanation :
Balanced chemical reaction : It is defined as the reaction in which the number of atoms of individual elements present on reactant side must be equal to the product side.
When solid calcium metal reacts with aqueous aluminum nitrate then it gives aqueous calcium nitrate and solid aluminium.
The balanced chemical reaction will be:

Answer:
6.54% is the required concentration of lithium in an alloy (Al–Li).
Explanation:
Suppose 100 grams of an alloy of aluminium and lithium.
Density of an alloy = d 
Volume of an alloy = V

Volume of aluminum = 
Mass of aluminum = x
Density of aluminum = 

Volume of lithium = 
Mass of lithium = y
Density of lithium= 

..[1]


..[2]
Solving [1] and [2] :
we get :
x = 93.46 g
y = 6.54 g
Concentration of Li (in wt%) that is required:

The Sea and the ocean are just different terms that mean same thing
I think the correct answer would be the last option. The ocean zone which has the lowest water pressure would be the uppermost zone which is the Epipelagic zone. This zone is also called as the euphotic zone or the sunlit zone. It is the region which receives the most sunlight in order to allow photosynthesis.