The answer would be nicotine.
Nicotine is an addictive substance. The type of nicotine that is found particularly in tobacco is nicotiana tabacum. It comes from the nightshade family of plants. Other forms of nicotine can also be found in tomatoes, potatoes, green peppers, and eggplants.
Cracks in a rock is considered is chemical weathering.
All living things are made of cells, so yes, mushrooms are made of cells. :)
When air is heated up the molecules spread out and move faster, so heat rises because it is less dense than the cooler air around it.
All of these have treatments with antibiotics.
