Fossil record of the first possible bipeds is the evidence exists that state humans are evolved in Africa. Modern humans arose in Africa at least 250,000 to 300,000 years ago, fossils and DNA are the evidence that reveals. Scientists have been unable to pinpoint a more specific homeland because the earliest Homo sapiens fossils are found all across Africa.
Humans first evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between 6 and 2 million years ago come entirely from Africa. Most scientists currently recognize some 15 to 20 different species of early humans found from Africa.
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s would be secondary Explanation:
just cause
I also believe the answer is A.
Important factor defining the desert biomes is its tendency to lose water by evaporation, and this potential for water loss exceeds the annual rainfall and defines what organism can live in there.
Answer:
Ashing process is done to evaluate the ash content present in petroleum or other proucts, so that they can be used for certain applications
The two major types of ashing process that includes dry ashing and wet ashing and can be performed using microwave systems or conventional means.
a. errors made in the preceding method while determining the ash content of buttermilk by conventional dry ashing are as following:
- Buttermilk should not immediatly put into muffle immediatley, it should be boiled first to avoid splatter.
- Temperature should be between 500 to 600 degree celcius at high temperature teh ash content can be loss.
- The sample should be ashed for 12-18 hrs
, more than this can damage the required ash content.
- platinum tip should be used in place of stainless steel because platinum has a lower concomitant tip impedance than stainless stell, so less reactive to ash.
- The ash should put in dessicator and not allow to kept in open because ash can react with the humidity in teh atmosphere.
b. The result that occur due to above errors such as the temperature, time, tongs and leaving ash in open will manipulate the final ash content and its application can be harmful for humans and for other purpose if it will be used.
