Answer:
ok so first of all try working hard then ill answer u
Explanation:
Answer:
D or A
<em>But I do know...</em>
It's because new strains of the virus are constantly appearing and evolving, so the vaccine must change along with them.
Alkali metal - Group 1 metal
Alkaline earth metal - Group 2 metal
Iron triad - metal
Halogens - most are diatomic and are nonmetals - Cl2, Br2, I2
Noble gases - nonmetals and are not reactive due to full valence shell.
Boron group - metalloid
Oxygen group - oxygen molecule - a diatomic molecule composed of oxygen atoms, which are nonmetals.
The act of using senses or tools to gather information is making an observation