On the planet earth. They exist in what we call the "world", which holds all seen life.
A membrane that allows only some materials to move in and out of the cell is B. Semipermeable.
Answer:Antibiotics disrupt essential processes or structures in the bacterial cell. This either kills the bacterium or slows down bacterial growth. Depending on these effects an antibiotic is said to be bactericidal or bacteriostatic.
Carbon atoms have 4 valence electrons. That allows them to make 4 covalent bonds. That means they can make really big molecules. All the organic molecules have Carbon in them.
