Answer:
Explanation:
Immunity to a disease is achieved through the presence of antibodies to that disease in a person's system. Antibodies are proteins produced by the body to neutralize or destroy toxins or disease-carrying organisms. Antibodies are disease-specific. Viruses make us sick by killing cells or disrupting cell function. Our bodies often respond with fever (heat inactivates many viruses), the secretion of a chemical called interferon (which blocks viruses from reproducing), or by marshaling the immune system's antibodies and other cells to target the invader. A vaccine works by training the immune system to recognize and combat pathogens, either viruses or bacteria. To do this, certain molecules from the pathogen must be introduced into the body to trigger an immune response.
These molecules are called antigens, and they are present on all viruses and bacteria.
Answer:
The roaches antennas
Explanation:
the roaches antennas sense movement from far so the antennas sense when the roach is in danger their for it moves away not towards it.
Answer: Crossing over is a biological occurrence that happens during meiosis when the paired homologs, or chromosomes of the same type, are lined up.
Explanation:
