Answer:
It is true that studying natural selection in the fields can be challenging. Some of the challenges which Darwin might have faced could have been:
Darwin was only studying one trait for his results. But there might have been many other factors or traits affecting natural selection.
Natural selection does not happen rapidly hence Darwin would have had to wait for many generations to observe the results.
The environment is not such an easy factor to study. It is complex. It might have happened that the environment might have changed before any changes were seen in the population of the birds.
The land and the aquatic are the two types of global food webs
The answer would be complicated
<span>.C. Seeds served as new means of dispersal for reproduction in areas without water.
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These type of plants are more evolved and developed than nonvascular plants because of its specialized characteristics like xylem, which is a tissue that is responsible for its framework and not only that, it is also has a greater mechanism for water transference. Another is phloem, which is responsible for food conduction.<span> </span>