<u>Answer:</u>
Recent evidence suggest that feathers evolved from scales and suggest that 'feathers and pycnofibers' could be homologous.
<u>Explanation:</u>
- One of the major difficult issue related to bird evolution is the evolution of feathers.
- Feathers are considered as the most 'complex integumentary structures' which are found in vertebrates.
- Evolutionary developmental biology suggests that the 'planar scale structure' is been modified for developing into feathers by 'splitting' to form web like structures.
- Scales and Feathers consist of 'two distinct form of keratin' so it was thought that 'each type was exclusive skin structure' but recent study suggests that they are developmental expressions of same skin structures.
Explanation:
the total mass of all the organisms in a representative area of the ecosystem C. the total mass of all the organisms in the ecosystem D. the number of organisms in each trophic level of the food web. leticiasilvacos is waiting for your help.
There are two daughter cells. The cell has split into two. The membrane has pinched together in the middle.
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