That it's bad and can hurt you.
"More harmful" and "most harmful." We would not use the -er and -est suffixes on the -ful which is already a suffix.
what are the danerous or harmful drugs
Insidious means proceeding in a gradual, subtle way but with harmful effects. It often refers to something harmful or dangerous that is not immediately obvious or easily detected.
HIV is harmful and dangerous.
It is not harmful but it dangerous.
For harmful, damaging, injurious, detrimental, negative, hurtful, destructive. For dangerous, hazardous, perilous, unpredictable, vulnerable, treacherous
very harmful
Noxious
The hazard symbol is a skull with crossbones - the meaning is death.
They can be dangerous if you don't treat them with respect.
It is useful!
is yeast dangerous or harmful