A standard contains a known amount of a substance. If u are performing an experiment you will use a sample with a known concentration to create a standard curve (a straight line). Positive and negative controls are measured against the standard curve to show the expected results if the sample u will be testing is positive or negative.
Because the lungs gradually, with the time, they lose their elasticity.
A Sticking to a nutrition plan
Answer:
i did't saw any oppstion so i gave some name of vegetables.
Explanation:
sweet potato
corn
beets
