Humans cannot digest food without the aid of small single celled organisms that live in our digestive tract these small organisms humans digest food by breaking down complex food molecules. which common name is associated with theses single celled organisms that humans digest food?

a virus
b protozoa
c bacteria
d algea

Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?