Answer:
2)
Explanation:
The positive control is the treatment where bacteria grew without lead. Since positive control indicates the presence of bacteria in the experimental conditions, it is possible to confirm that they only death in presence of this metal. However, it is important to note that it is imperative to repeat this experiment three times and also to include a negative control in order to confirm these results.
D. Asteroids vary greatly in size and are mostly made up stone, iron and nickel
Answer;In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.
Explanation:
Answer:
muscles
ribs
lungs
bronchioles
alveoli
diffuses
leaves
exchange
Explanation:
Your diaphragm, and <u>muscles</u> between your <u>ribs</u>, make air move in and out of your <u>lungs</u>. It travels through the trachea, bronchi, and <u>bronchioles </u>to <u>alveoli</u>. In the alveoli, oxygen <u>diffuses</u> into the blood and carbon dioxide<u> leaves</u>. This is gas <u>exchange</u>.
<em>Air enters the lungs and leaves it as a result of the relaxation and contraction of the diaphragm and the muscles between the ribs. When both the muscles and the diaphragm relax, air enters from the trachea and travels through the bronchi and the bronchioles to the alveoli, where the oxygen in the air diffuses into the blood and carbon dioxide diffuse in the opposite direction. The entire process is known as gas exchange.</em>
