There are gaps in the fossil record because many early forms of life were soft-bodied, which means that they 14
There are many different species of bird on the Earth today.
Describe how these different species may have evolved from an ancestor such as
Archaeopteryx.

By studying fossils, scientists can learn how much (or how little) organisms have changed as life developed on Earth. There are gaps in the fossil record because many early forms of life were soft-bodied, which means that they have left few traces behind. ... This is why scientists cannot be certain about how life began.

thymine. in rna, thymine is replace by uracil

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