A teacher is preparing the materials list for an activity that all 6th graders will complete. Each student will create a scale model of the planets in Earth's solar
system. A student will need 2,250 mg of clay to create a model of Mercury.
What two conversion factors will the teacher need to use in determining how
many kilograms of clay to order?

There are 1000 mg in 1. g

There are 1000 g in 1 kg

Each students needs 2,250 mg of clay

Explanation:

In order to determine the amount of how many kilograms to order, the teacher will need to find out the total mass of clay required by the students and then the teacher will have to convert the total mass to the units required for the purchase.

The teacher would have to find out how many milligrams make one kilogram as follows

1 kg = 1000 g

1 g = 1000 mg

Therefore, 2,250 mg = 2250/1000 g = 2.25 g

2.25 g = 2.25/1000 kg = 0.00225 kg.

it's all four options.