Answer:
D) Chromosomes can align in metaphase I in multiple possible arrangements in a process called independent assortment.
Explanation:
The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.
1. Rainforests only cover around 2 percent the total surface area of the Earth, but really about 50 percent of the plants and animals on the earth live in the rainforest.
2. There are two different types of rainforests, and they include both temperate and tropical. The tropical rainforests are the ones that are most commonly found around the world.
3. A fifth of our fresh water is found in tropical rainforests, the Amazon Basin to be exact.
4. Within four square miles of tropical rainforest, you will find 1500 flowering plant species, 750 types of trees, and many of these plants can be helpful in combating cancer.
5. Rainforests are threatened each and every day, especially by practices such as agriculture, ranching, logging and mining.
Hope this helps!
~Starr
