What is the largest organ in our body and is our first defense against germs and bacteria?

What is the top layer of skin called?

What is the second (middle) layer of skin called?

What is the third (bottom) layer of skin called?

The purpose of the immune system is to:

The immune system is made up of:

As part of the immune system, white blood cells fight germs. Another name for white blood cells is:

Leukocytes are found in lots of places, including an organ in your belly that filters blood and helps fight infections known as the:

The four main types of germs are:

Getting these when you’re young helps your immune system fight off diseases:

These cells carry oxygen to all of your other cells in your

body.

Which blood components fight infections by attacking bacteria/viruses

The yellowish fluid part of blood is called...

True or False?

Platelets are blood cells that help blood to clot when we get a cut.