A Pure Substance That Cannot Be Broken Down into Another

question 39

Multiple Choice

A pure substance that cannot be broken down into another substance is known as a(n) ____.

• A)proton
• B)electron
• C)compound
• D)element
• E)isotope

---

Definitions:

Plasma Membranes

A dual lipid layer enveloping the cell's cytoplasm, responsible for managing substance movement into and out of the cell.

Cell-mediated Immunity

A branch of the immune response that involves the activation of T-cells to fight off intracellular pathogens and cancer cells.

Cytotoxic T Cells

Immune cells that kill cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways.

B Cells

A type of white blood cell that plays a vital role in the immune response by producing antibodies to fight off infections.