For the frog heart, temperature and heart rate are "directly proportional."
Answer:
Deforestation and the burning of fossil fuels
Explanation:
Deforestation leads to less carbon dioxide to oxygen production, and burning fossil fuels releases large amounts of carbon dioxide.
Mutation...are there answer choices?
Answer:
Submerge a leaf in boiling water for one minute. This kills the leaf as it destroys membranes, making it easier to extract chlorophyll.
