1) Hunting: People can over-hunt a species killing too many of them too fast.
2) Global warming: A place can get to hot for them to survive their anymore like coral reefs for example.
3) Destruction of habitats: This can leave animals defenseless and open to attack.
People with an aa genotype will express a recessive trait
Weather. This includes factors like temperature, humidity, wind speed, etc.
An occluded front is usually associated with severe thunderstorms or a drizzle.
You see how much the scale is, let's say that it is 150 mm=300 miles. If it goes over, you can measure it with a ruler, or move with your hands, measuring it as well as possible and estimating. Hope this helps! :)