Which owhich of the following gases is not found in earth s atmosphere?
a. oxygen
c. hydrogen
b. nitrogen
d. all of the above are in the atmosphere f the following is not a major gas of earth's atmosphere?

Aplane cuts a pyramid as shown in the diagram. what is the shape of the cross section? a. a hexagon b. a pentagon c. a square d. a triangle

Which of the following is an example of an outdated theory based on the consensus of the scientific community ? a. big bangb. geocentric solar systemc. heliocentric theoryd. plate tectonics answer : geocentric solar system

Which ecosystem best fits the characteristics listed below? which ecosystem best fits the characteristics listed below? ii. seasonal migrations of millions of wildebeests, zebras, and elephants iii. large numbers of predators, such as lions iv. acacia trees and grasses a. the congo rainforest b. the african mangroves c. the serengeti grasslands d. the sahel