Answer:
1. Skull and crossbones
2. A triangle (commonly painted colour red or yellow) with an exclamation sign inside.
3. biohazard symbol
4. A radiation sign in the form of a triangle, having other little image descriptions inside.
Step-by-step explanation:
Note that a biohazard material refers to dangerous substances of biological (living) nature that can pose a threat to humans. Thus, safety symbols try as much as to draw attention to the descriptions used.
For example, skull and crossbones and biohazard symbols are used to indicate that a material that is biohazard, such as bacteria could result in the death of a person.