Question

What is a substrate?

Answer 1

A substance or layer that underlies something, or on which some process occurs, in particular.
• the surface or material on or from which an organism lives, grows, or obtains it's nourishment.
• the substance on which an enzyme acts.

Answer 2

Hey there!

A substrate is a substance that is placed under something.
Substrates are substances that are placed under many things, such as a built bed frame, but there are many other things/examples in which they are placed in.

Hope this helps you.
Have a great day!