yes there are many helpful microbes like lactobacillus that helps in making some milk products
rhizobium helps in nitrogen cycle
Not all microbes are harmful. Some are quite helpful. As humans, we actually have microbes in our bodies and on our skin that work to keep us from getting certain diseases.
Toothpaste helps in killing pathogenic microbes. I don't think it itself contains any microbes.
Most microbes don't cause any harm at all, and many of them are actually helpful, like the ones in our digestive system. Only a very few microbes are hazardous and they generally come if two main varieties depending on their shapes. One is strep and the other staph.
Microbes can live in almost any and every condition. Anywhere you go, you can find some kind of microbe that has adapted to living there.
If an antibiotic is used excessively, it may destroy too many of the harmless and helpful microbes in the body, and it may result in the development of a strain of harmful microbes resistant to the antibiotic so that it will no longer be effective in killing them.
We will all gonna be in trouble if these microbes are destroyed because microbes decomposes us and break us down.They will never keep us from accumulating any more.
This will occur primarily when good microbes win the battle with [or out-compete] the bad ones for 'living space'. All must share this space equally or else an unhealthy, off-balance, concentration of germs would exist.
Any drug can be helpful. Any drug can also be abused.
Waxes, such as that found in the ear, provide a helpful barrier against infection. Earwax collects dirt and microbes that might otherwise enter the body.
Microbes evolve. Those which are better able to survive the drugs that people use to kill them will be more likely to give rise to new generations of microbes. It works exactly the same way as any other form of evolutionary pressure.
1) Prokaryotes2) Bacteria3) Archaea4) Eukaryotes5) Protists6) Micro-animal7) Fungi8) Plants