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.
Answer:
C
Explanation:
neon doesn't make up the atmosphere... or does it jk it doesn't
These components include;
Cardiorespiratory Endurance: Ability of the circulatory and respiratory systems to supply oxygen during sustained physical activity.
Guidelines
3 - 5 days per week
20-60 minutes a day
intensity of 60%-90% of MHR
Muscular strength; the ability to perform activities that require high levels of muscular force.
2 -3 days per week
2-6 sets
≤ 6 repetitions
Intensity of 80 - 90 % of 1RM
Muscular endurance;
2 - 3 days per week
2 - 3 sets
≥ 12 repetitions
Intensity of 60% - 70% of 1RM
Flexibility
2- 3 days a week
≥ 4 repetitions per muscle group
15 - 60 seconds
Body composition Women men
Essential fat 10-13% 2-5 %
Athletes 14-20% 6-13 %
Fitness 21-24% 14-17 %
Average 25-31% 18-24%
Obese ≥ 32% ≥ 25%
What this student thought was happening is called spontaneous generation. Spontaneous generation is a body of thought on the ordinary formation of living organisms without descent from similar organisms
HOWEVER, the student was wrong because it is impossible for organisms to be spawned out of nothing. The organisms appeared due to bacteria on the meat and in the air.
