Answer:
Water sample showing pink/purple color is an error.
Explanation:
Biuret is a blue color reagent that changes its color to pink/purple whenever it detects protein in a sample. Water don't contain proteins so it should not show pink/purple color instead it should maintain the blue color. Food items generally contain proteins so it show pink/purple color but it showed blue color.
Error might have caused by wrong marking of the samples, test tube marked with Water might contain a mystery food while Mystery food tube might contain water.
Answer:
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.
The organisms<span> that eat the producers are the primary consumers. They tend to be small in size and </span>there<span> are many of them. ... Because of this inefficiency, </span>there<span> is only enough </span>food<span> for a </span>few top<span> level consumers, but </span>there<span> is lots of </span>food<span> for herbivores lower down on the </span>food chain<span>.</span>
