Rattlesnakes are entirely beneficial as long as they are left alone. They consume large numbers of rodents which can carry diseases harmful to humans and they damage or destroy human food and crops. If you mess with rattlesnakes, however, you could end up in the hospital for several days being treated for a venomous snakebite.
If they bite you you could have real problems, however their poison can be extracted and help in creating an antidote
most people try to harm snakes or kill them because they are so afraid of them so the don't come near
If you need help I recommend you type in the specific question you need help with
it can be helpful or harmful
sometimes they are helpful and harmful.
Bacteria can be both harmful and helpful
Sandpaper is both helpful and harmful.
they are helpful not harmful to plants
harmful
Depends on what part of "harmful" or "helpful" you are referring to.
helpful
Helpful
helpful
Harmful bacteria will harm you. Helpful bacteria will help you.