Magnesium oxide can be very bad for your health, and when we did an experiment with it in class it was white because it was so hot. It is very flammable.
Hi , basically dominant alleles are always expressed in the organism , while recessive traits tend to be expressed only when the dominant allele is not present.
Answer : The correct options are,
and 
Explanation :
Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.
Option A reaction : 
It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.
Option B reaction : 
It is an example of single displacement reaction.
Option C reaction : 
It is an example of combination reaction because in this reaction two reactants react to give a single product.
Option D reaction : 
It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.
Option E reaction : 
It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.
Hence, the options B and E are single displacement reactions.
Answer: Avogadro's Law
Explanation: It states that the volume of the gas is directly proportional to the number of moles of the gas at constant pressure and temperature of the gas.