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Some time after the first stars lit off, so about 13.5 billion years ago.
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∙ 6y ago
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Does oxygen should have existed for the chemical evolution of life on earth to have occured?
its oxygen
How is theory of evolution of Darwin and Hugo deVries different?
Darwin considered evolution to be caused due to : 1)small changes/variations that occured 2)these variations were directed specifically towards adapting to the environment(directional) 3)evolution was a slow process De Vries believed that evolution occured by: 1)large changes that occured 2)these changes were mutations and were stochastic or random, not directional 3)evolution occured in fits and starts and was not a slow ongoing process
How does the chemical equation show that a chemical reaction has occured?
A compund
When substances are different from the starting substances what occured?
This is a chemical reaction.
When a substance changes into a difference substance a what change has occured?
chemical change
What are 2 types of evidence that suggest that evolution has occured?
Accept fossil evidence, anatomical evidence, molecular evidence
What do scientists call an area along fault where no earthquake activity has occured for a long time?
a seismic gap
What happens in a can of spoiled food as gas is produced?
A chemical reaction of food decomposition occured.
When a metal changes color because it has reacted with another substance and what change occured?
Chemical
What are three clues that a chemical change has occured?
Three clues that a chemical change has occurred:Color changesa precipitate formsa gas forms
When do scientists believe the last ice age occured?
We are in an ice age now. The last glaciation ended about 10,000 years ago depending on which part of Earth you live. There have been many glaciations during the past 2.6 million years.
If you put water in a freezer and it turns to ice what kind of change occured to the water?
A chemical change occurred
