To perform this test to check if gold is real, make a light, tiny scratch on the item using a small nail file. Choose a spot that is not noticeable if possible. Use a dropper to apply a small drop of nitric acid to the scratch. If there is no reaction, then the piece is probably made from real gold.
cholesterol in the cell membrane is to maintain stability, anchor other molecules, and keep the membrane fluid in cold temperatures.
Ok this might not be the best answer but just by reading it, it may be unreliable because numbers do change over time
The similarity between directional and disruptive is that both are types of selection on polygenic traits in which the curve shift away from the middle.
The different between disruptive and directional is in disruptive move toward both ends . And in directional, the curve shift toward one end.
