How did farmers observed by Charles Darwin take advantage of natural variation to improve their livestock?

They used artificial selection

Explanation:

Breeding animals who had desirable or good traits. For example, they bred cows who produced the most milk and plants that produced the most vegetables. :))

creative diagnostics provides a protocol for total protein extraction based on ripa which is widely used.

one is through turgidity. this occurs before ground tissue ( collenchyma

and sclerenchyma cells) become well

developed to give structural support to the plant as it grows bigger. the xylem

tissue (composed of rigid tissue) of the young

plant render this support and also maintaining osmotic turgidity of the surrounding

plant cells.