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.
All plants have a cell wall, all mammals have a cell membrane. a cell membrane is semi-permeable it allows mammal cells to absorb needed nutrients, oxygen and deposit waste into the blood stream where it is excreted through urine and feces. a plant cells nutrients are absorbed through the root system and leaves, waste is excreted in the form of oxygen through the plant itself.
Phospholipids are typically made up of two fatty acids,a glycerol molecule and a phosphate group that is modified by an alcohol.The phosphate group is negatively charged, it is hydrophilic and it is describes as the polar HEAD of the phospholipid. The fatty acid chains have no charge [neutral], they are hydophobic and they are describe as the non-polar TAIL of the phospholipid.
C. The temperature remains the same.