What does a closed circulatory system mean? a) The blood travels through a systemic circulation, which includes the heart and body, and a pulmonary circuit with included the heart and lungs
b) the blood flows through the heart once during each circulation of the body
c) Blood always stays entirely inside the blood vessels. A separate fluid called tissue fluid bathes the tissues and cells​

I’m stuck on this question cuz i’m stupid sksksksk

You find a fossil that you are sure shows evidence of bipedalism. you know this because which of the following anatomical traits is present? a. thighbones that angle in toward the knees b. a narrow pelvis c. opposable hallux d. posterior position of the foramen magnum

Which of the following is true about the introduction of a non-native species to an environment? (a) they usually adapt quickly so they can have a positive affect on the environment. (b) they can disrupt the environment and cause much damage and devastation to native species. (c) they usually become predators in a food chain and to keep prey populations under control. (d) because the native species are better-adapted to the environment, the non-native species always end up dying out.