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baherus [9]
2 years ago
12

3. What are some scientific explanations for the history of life on Earth?

Biology
1 answer:
KATRIN_1 [288]2 years ago
7 0

Answer:

Many scientists favor the RNA world hypothesis, in which RNA, not DNA, was the first genetic molecule of life on Earth. Other ideas include the pre-RNA world hypothesis and the metabolism-first hypothesis. Organic compounds could have been delivered to early Earth by meteorites and other celestial objects

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By age 65, what percentage of adults are grandparents? 75 80 85 90
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85% of adults are grandparents by age 65. This estimation has been made in the U.S. from the surveying of the elderly. So, the correct choice is the third option: 85. 

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                - Dotz
7 0
3 years ago
Which describes gas exchange in the respiratory system?
hichkok12 [17]

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4 0
3 years ago
From the sequencing of the human genome, we believe that there are approximately 21,000 protein-coding genes in the genome, of w
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