14. which of the following natural processes ...
14. which of the following natural processes most likely led to landform in the following diagram?\n15. which body system is responsible for supplying o₂ to body cells and taking co₂ away from body cells?\n a. circulatory system\n b. respiratory system\n c. digestive system\n d. the skeletal system\n16. a helium atom has 2 protons in the center of its nucleus. its mass is greater than the mass of these two protons. which of the following accounts for this difference in mass?\n a. electrons\n b. neutrons\n c. protons\n d. the skeletal system
Answer
# Brief Explanations:
14. The diagram shows a sink - hole which is often formed by physical weathering processes like dissolution of limestone by water. Physical weathering breaks down rocks without changing their chemical composition.
15. The respiratory system is responsible for gas exchange, supplying oxygen ($O_2$) to body cells and taking carbon - dioxide ($CO_2$) away from body cells. The circulatory system transports these gases, but the actual gas exchange occurs in the respiratory system.
16. A helium atom has a mass greater than the mass of its two protons because it also contains neutrons in the nucleus and electrons around the nucleus. Neutrons have mass and although electrons have very little mass compared to protons and neutrons, they also contribute a small amount.
# Answer:
14. a. Physical weathering
15. b. Respiratory system
16. c. Neutrons and electrons