The right option is a. contour interval
The difference in elevation between the highest and lowest contour lines on a topographical map is called contour interval.
A contour interval is the vertical distance between the two contour lines (highest and lowest) in a topographical map. The contour interval is usually stated explicitly on the right-hand lower part in every map. 20 feet for a 1:24,000 map scale is the frequently used contour interval and different contour intervals is available for different maps.
Answer:
When CO2 is breathed into the lungs, it dissolves in the water there, diffuses across the alveolar-capillary membrane, and enters the bloodstream. As it combines with water, it forms carbonic acid, making the blood acidic. So CO2 in the bloodstream lowers the blood pH.
The answer is B because the humoral immune response is mediated by antibody
