The correct answer is A. Tundra
Explanation:
The tundra is a biome characterized by low temperatures or polar climate (temperatures under 10°C) due to this, in the tundra, only small shrubs, grasses, mosses or similar thrive as wells as animals such as reindeers, arctic foxes, hares, etc. This biome is the one presented in the Artic (Northern Hemisphere), the Antartic (Southern Hemisphere) and the Alpine in Europe. Additionally, in tundra, the subsoil is permafrost which means there is a layer in the soil that is constantly frozen (below 0°C). According to this, the biome the biologist is studying is the tundra as this is the biome with very low temperatures and permafrost.
