A, B and D because a food web shows eating patterns and how that energy is exchanged.
Conduct research and experiments to improve the productivity and sustainability of field crops and farm animals
Answer:
The answer is age.
Explanation:
So for a 50-year-old, maximum heart rate is 220 minus 50, or 170 beats per minute.At a 50 percent exertion level, your target would be 50 percent of that maximum, or 85 beats per minute.