Answer:
Explanation:
African trypanosomiasis is a parasitic disease transmitted by the tsetse fly. It gets its nickname 'sleeping sickness' because symptoms can include a disturbed sleep pattern.
Valves ensure blood flows toward your heart. Vein valves work to bring the blood that flowed down via arteries back up to your heart.
A hypothesis cannot be wrong, because it is an educated guess. You cannot prove a guess wrong. A guess is something you think, and there is no right or wrong answer to thoughts.
Answer:
Theory
Explanation:
A scientific theory means an idea which is true and tested.
