Mohammad is studying the growth of a particular type of plant. He is testing the effects of three growth factors: lighting, age, and temperature. Here are the levels he's testing for each.

Growth factor
Levels

Lighting
None, Low, Medium, High, Very high

Age
1 month, 2 months, 3 months, 4 months, 5
months

Temperature
20 °C, 22 °C, 24 °C, 26 °C

He wants to find the number of ways of combining one level from each of the growth factors. How many ways are there?