What is an allergen?
A chemical substance released by the immune system in allergic reactions that is responsible for many of the symptoms of anaphylaxis, such as vasodilation
A poison or harmful substance
A raised, swollen, well-defined area on the skin resulting from an insect bite or allergic reaction
A substance that causes an allergic reaction

Use the drop down menus to match each example to the fossil topic discussed then to show how the fossil record gives evidence of evolution

Which element forms the basis of all organic organisms a carbon b oxygen c hydrogen d nitrogen

Students in biology are studying the macromolecules of life. they used a calorimeter to determine the calories in various types of food. once the lab was completed, the students ate the left over food samples. monica commented that in just 6 or 7 "chews" of the saltine, it was gone; nothing but a sticky paste in her mouth. elaborate on what happened chemically while chewing the saltine. include the macromolecules present.