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:
Natural resources are not evenly distributed all over the world. Some places are more endowed than others — for instance, some regions have lots of water (and access to the ocean and seas). Others have lots of minerals and forestlands. Others have metallic rocks, wildlife, fossil fuels, and so on.
Explanation:
A hormone is a molecule that functions as a chemical signal. A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Endocrine hormone molecules are secreted (released) directly into the bloodstream. !
Answer:
total amount spent on student ticket = 186($2.5)=$465.00,
Total amount spent on adult tickets = 135($3.5)=$472.50
Explanation:
cost total = student ticket price (x) + adult ticket price (321 - x)
$937.50 = (2.5)(x) + (3.5)(321 - x)
$937.50 = 2.5x + 1123.5 - 3.5x
x = 186, therefore 186 student tickets sold,
(321-x) = 321-186 = 135, therefore 135 adult tickets were sold.
total amount spent on student ticket = 186($2.5)=$465.00,
Total amount spent on adult tickets = 135($3.5)=$472.50
So the total amount spent on tickets was
$472.50 + $465.00 = $937.50
In McMillen and Austin’s research (1971), participants who had lied were more likely to volunteer a large amount of time.
Explanation:
The research work conducted by Mcmillen and Austin in the year 1971, included college students as participants of the research. In this process they are asked to perform a small test of intelligence. One portion of them was asked to cheat and lie and the rest were left not to cheat.
After finishing the test, the participants were asked to help the administrator to conduct the next round of test for other slot of participants. It was seen that the students who did not lie or cheat, helped them in their work for about 2 minutes. But students, who did lie, stayed and helped for 53 minutes.
