D.) black text on a yellow background. There is much more contrast in the colors black and yellow than the other choices.
Answer:
The heart and the blood vessels are a part of the circulatory system. The blood vessels include the arteries, veins and capillaries. The lungs are considered to be the pulmonary part of the circulatory system. The heart is the cardiovascular part of the circulatory system and the vessels are the systemic part of the circulatory system. The main function of the circulatory system is to supply all parts of the body with oxygenated blood and to take away the deoxygenated blood from all parts of the body.
German scientist Döbereiner was one responsible for grouping elements into triads based on most notably atomic mass, many of which can be found in the periodic table to be in a pattern (for example <span><span>Iron </span><span>Cobalt </span><span>Nickel, elements 26, 27, 28)</span></span>
C. The mass number is the amount of Protons and electrons there are combined, so 200 - 80 is 120.