What is so special about Earths climate change over the last 5 years???

Not sure if you have any specific answers to be looking for, but the ozone layer is consistently decreasing, arming up the globe - which causes us to lose ice and the oceans to warm, which exposes us to harmful pollutants/radiation/chemicals/etc. otherwise absorbed by the waters.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.