On Earth it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium<span> present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of </span>helium<span>-4 nuclei.</span>
Answer:
Physical change
Explanation:
It is a physical change because a physical change involves alteration in physical properties or appearance in color, sizes e.t.c but no new substances is formed. From the question, CoCl2 undergo a physical change because it's physical property which is color changed , its composition is not altered or no new substances is formed during the reaction.
Its mass will stay the same
Explanation:
Population is hugely dependent on the environment and it's factors. The physical, chemical and biological components of the environment plays vital roles in the sustenance of all life on earth.
A change in the environment can lead to terrifying consequences. Let's examine some of the changes:
- Climate change can lead to flooding of biological habitats and where people typically reside. This can lead to death and loss of life.
- Drought can lead to decline in food production. During a drought, a place receives little to no rainfall and the land is not fit for agricultural practices. This will eventually lead to famine.
- Pollution: it is the introduction of harmful substances into the environment. Pollution is harmful to the population.
- Geological hazards; earthquakes, volcanic eruptions,mass wasting and so on can lead to a crash in population.
- Wildfires, tornadoes, dust bowls e.t.c are changes in the environment that can cause severe consequences on the population.
Learn more:
Environment brainly.com/question/3906722
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