The correct answer should be B. Small regions interspersed with other biomes. This type of a biome is found on all continents and in many countries. It's specific because it's similar to a desert when it comes to yearly precipitation, but it is different insofar that it has a lot of plants and animals that are mostly nocturnal predators.
Over time, as oxygen levels decrease, CO2 levels increase. Respiration is correct as it uses oxygen as a reactant and releases CO2 as a byproduct.
