Answer - It is a Great Concern because microbes such as a hydra can consume some of that mercury which then a shrimp can consume that microbes which then transfer into the mouth of a trout which then when humans fish they consume the fish which later we get Mercury poisoning.
Reasoning - There are more concern but these are a few and some reasoning.
Answer:
There would be no seasons anywhere on Earth
Explanation:
If the Earth's axis was not tilting and it was at a 90 degrees angle relative to its orbit, then the seasons on Earth would disappear. The climate on the planet would be defined by the latitude. The equator and the areas close to it would always have summer, as they will receive direct sunlight throughout all of the year. The mid-latitudes will always have temperate climate, reminding of spring and autumn, as the sunlight will not be very direct, but it will also not be very dispersed, jut enough to create a constantly pleasant climate. The higher latitudes will always have winter, as the sunlight will come at a very low angle throughout all of the year, thus it will be very dispersed, not enough to ever warm this parts enough, so they will constantly be under ice.
Because any other substance couldn't carry the heat and the amount of surface area gives it more of an opportunity to cool down