Your body used the respiratory system (lungs)
It is Big Bang and cannot be proved. A hypotheses must be testable. Big Bang is not testable.
Well, ask yourself, "Do I try hard enough?" "Was it the best I could do?" And well if the answer is yes, then you have nothing to stress out about too much. Maybe talk to your teacher and ask for extra credit. Get tutoring. Talk to a guidance counselor. If none of that helps, well then you're just not the best at the subject, but just try your best. In the future, you won't even remember about all those grades! Coming from a 6th grader, the beginning of the year was super hard. I'm not the best at math, but I'm very good at Language Arts. Everyone has their own weaknesses and strengths. Don't worry about it.
I believe the correct answer from the choices listed above is the first option. A lamprey is characterized by an absence of jaws. This animal is have no jaws and are only full of teeth. <span>Lampreys are any jawless fish of the order Petromyzontiformes. Hope this answers the question.</span>