durante uma aula prática no laboratório, os alunos visualizaram no microscópio dois tipos de células, uma eucarionte e uma procarionte.

Which of the following occurs after a natural or unnatural disturbance in an ecosystem

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

Select the correct answer. which statement applies only to the axial skeleton, not the appendicular skeleton? a. it contains a pivot joint. b. it has muscles attached that work in pairs. c. it contains red bone marrow. d. it possesses fossa for bone articulation. e. it protects the heart and lungs.