I think sister groups. Imagine them having the same parents.
Answer & Explanation:
Here's the order of the planets, starting nearest the sun and working outward through the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune — and Planet Nine.
Explanation:
The role of active cytotoxic T cells is to attack <u> </u><u>body cells that have been infected</u>
