Answer:
Biotic and Abiotic factors
Explanation:
Biotic factors such as predators can limit the population size.
Abiotic factors such as drought,torrential rainfalls,climate change,dessication etc.
Answer:
haemoglobin
Explanation:
Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body