Answer:
O During photosynthesis, plants take in carbon dioxide from the air.
Answer: OB
Explanation:
The empirical formula of an element is the simplest formula of an element which shows the ratios of atoms of the each element present in a molecule of a compound .
Answer :
According to the law of conservation of mass, the mass of reactants must be equal to the mass of products.
The balanced chemical reaction is,

As we know that the molar mass of magnesium is 24 g/mole, the molar mass of
is 32 g/mole and the molar mass of magnesium oxide is 40 g/mole.
From the given balanced reaction, we conclude that
As, 1 mole of magnesium react
mole of oxygen to give 1 mole of magnesium oxide.
So, the mass of Mg is 24 g, the mass of
and the mass of MgO is 40 g.
That means 24 g of Mg react with 16 g
to give 40 g of MgO.
An electron i hope this helps
Most solids a) are dense and difficult to compress.
Most solids are closely compacted, their molecules are close together and vibrate. They don't move freely like gas or water molecules do.
They are difficult to be squeezed or flattened.