Which best explains why conservation of mass should be studied in a closed system?
A. to prevent contamination of the products
o
B. to prevent the loss of any reactants
c. to prevent the release of any gases produced
D. to prevent the absorption of heat from the outside

C

Explanation:

a. a primary source combines several different accounts of an event. b. a primary source generally benefits from having been written after an event.

explanation:

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.