Simple. Air has mass. And if air has mass it also has weight. You can feel air when the wind blows. Or do an experiment. Weigh an empty container. Then pump it to a vacuum. Weigh it again. The difference is the weight of the air inside.
The bacterium is not susceptible to the penicillin family of antibiotics. it contains no plasmids and relatively little peptidoglycan. Adherence to the intestinal lining by this bacterium is due to its possession of a capsule.
clay soil is a hard kind of soil, since its hard its not loose. sand is what drains quickly, clay drains slowly and retains water for much longer than sand does.
