Chemical bonds.
Chemical bonds hold the atoms of a molecule together thereby forming covalent bonds, when two atoms share electrons.
Interphase-intermediate phase, DNA replicates
Prophase -coils into chromosomes, chromosomes are made of two chromatids, which join at the centromere at this stage.
Metaphase -Chromosomes line up in the middle of cell on spindles
Anaphase - Chromosomes are pulled apart to opposite ends of the cell by the spindles
Telophase - The cell splits into two cells, and the chromosomes uncoil and begin from the interphase stage again
Foreign invaders have proteins called antigen, which antibodies lock onto to neutralize. The foreign proteins are different from proteins in our own body, so the immune system can recognize them and finally eliminate them.
Bacterial infections were much harder to treat a long time ago because we didn't have the same technology or information that we do now. because we have worked so long on treating different things we have learned what works and what doesnt. the new technology has helped us understand the infection which led to us being able to find medication to treat said infection.
Need more information to answer the question.
