This question isn't very specified but i'm pretty sure by the context the answer is gonna be tree frogs.
<span>The answer is enzymes. Enzymes are biological catalysts and increase the speed of change from substrate to product. The name of enzymes is usually derived from the substrate they break down. For example, lactase breaks down sugar lactose. The name of enzymes contains suffix -ase, for instance, carbonic anhydrase, lactase, lipase, amylase, etc...</span>
Answer: Our immune systems are different and we come from different areas were exposure rates may be different.
Explanation: