Question

select all the reactants

Explanation:

Step1: Identify Reactants in Equation

In a chemical reaction, reactants are on the left of the arrow. The top left shows two Mg (gray) and a red diatomic molecule (O₂, since product is MgO). Below, the middle has two Mg (gray) and the right has red diatomic (O₂). Wait, no—original top left: two Mg (gray circles) and red O₂. So reactants are Mg (the two gray Mg circles) and O₂ (red diatomic). Looking at the bottom options: middle has two Mg (gray, labeled Mg), right has red diatomic (O₂). The left bottom is product (MgO, red and gray). So select the middle (two Mg) and right (O₂) as reactants. Wait, the task is to select all reactants. So the middle box with two Mg (gray circles labeled Mg) and the right box with red diatomic (O₂) are reactants. The left bottom is product (MgO), so not reactant.

Step2: Confirm Reactant Selection

Reactants are substances before reaction (left of arrow). So the two Mg (middle box) and O₂ (right box) are reactants. The left bottom is product (MgO), so exclude. So select the middle box (two Mg) and the right box (red diatomic O₂).

Answer:

The middle box (with two "Mg" labeled gray circles) and the right box (with red diatomic molecules) are the reactants. So select the middle box (containing two Mg atoms) and the right box (containing the red diatomic molecule).