Ragweed antigens bind ragweed and then bind mast cells which release histamine
<span>Allergies develop because of a Th2 response against the allergen. </span>
These animals were living in an environment with a warm climate that results in changing sea levels. These conditions create a lot of shallow inland seas allowing these animals to thrive. The Cretaceous period is the last period of the Mesozoic area where new groups of mammals, birds, and flowering plants appeared on Earth.
I'm not certain on the reason it happens, but it can be lethal by stopping the heart from beating and, the lungs from contracting and expanding causing death by suffocation or cardiac arrest, also putting the body into shock.
