Answer: aluminium, mercury , platinum and copper.
Explanation:
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.
A general single displacement reaction can be represented as :

Thus the metals which are more reactive than magnesium will react with magnesium sulphate solution.
The metals which are more reactive than magnesium are aluminium, mercury , platinum and copper.
Circle-Thus a circle has the largest area of any closed figure with a given perimeter
Answer:
When magma reaches the surface, its dissolved gas content increases is true
<u>Explanation</u>:
The volcanic eruptions happen because of magma that is expelled on the earth’s surface. At the earth’s depth, all magma have gas dissolved in liquid. When the pressure has decreased the magma rises towards the earth’s surface creating a separate vapour phase.
As pressure reduces the volume of gas will expands and giving magma its 'explosive character'. Thus, as magma reaches the surface the dissolved gas content decreases and magma comes out of earth’s surface.
Answer:a reddish- or yellowish-brown flaky coating of iron oxide that is formed on iron or steel by oxidation, especially in the presence of moisture.
Explanation: so basically rusting happens when a metal comes in contact with moisture and air, at a brown, dirty metal coat forms on it.