Reindeer roam over hundreds of miles to search for food the have a far reaching A-Niche
B- Habitat
C- Community
D- Ecosystem

B. Habitat

Explanation:

Ecosystems are geographical regions made up of biotic factors (plants, animals, bacteria) and non-living or abiotic factors (rocks, rainfall, temperature).

They live in groups called communities within their ecosystem and occupy a specific place in their community, a niche - here, they contribute to nutrient cycling and energy flow. They may often wander in search of food, or shelter in a region known as a habitat.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

the food storage products of chrysophytes are oils or the polysaccharide laminarin.   formerly classified as plants, the chrysophytes contain the photosynthetic pigments chlorophyll a and c all but the yellow-green algae also contain the carotenoid pigment fucoxanthin.