Bacteria can be both harmful and helpful
Sandpaper is both helpful and harmful.
they are helpful because they are
They are more helpful than harmful. My two gerbils are both helpful. They've helped me in many ways and so that's why I say they're more of helpful than harmful.
Both only when it infects it is harmful
Both
both
blue whales are active in both day and night.
They are helpful because they clean out intestines. they are harmful because they can cause diseases
computer.. both helpful and not..
a bacillus bacteria
They are not harmful they are verynice animals they do not hurt anyone or anything.