I belive that the emperor penguin fits all the criteria of Group B.
Answer: It would probably be A.
Explanation: Abrasion means scraping or wearing away. Therefore the correct sample is probably going to look smaller, smoother, and more even from all the scraping of the river currents.
Hope that helps!
Carbon dioxide because people in other animals exhale carbon dioxide as a waste product. People and other animals need oxygen for plants produce oxygen during an important process called photosynthesis which turns the sun energy into nutrients so carbon dioxide would be the answer.
