C) I and III only just got this question on usa test prep and therefore i'm right
I guess because of concentration.....it stops !
The right option is; c. biomes
Savanna is considered a transitional biome because it is intermediate between two biomes.
A savanna is a tropical grassland ecosystem that is characterized by widely spaced scattered trees. Savanna is an extensive plain that is regarded as a transitional biome because it is intermediate between moisture equator forests and tropical deserts. It covers about 20% of the earth’ surface. Savanna has seasonal water availability and during the dry season, there are strong evaporation which makes the trees such as baobab to shed their leaves while bushes and grasses wither.
Lipids provide long term energy storage
D-walls and doors would represent the cell membrane