Biology

Siena

17 May, 01:15

Many birds live in mountainous temperate forest ecosystems. Above the tree line on mountains, however, the ecosystems change. Few birds are found there. Many factors contribute to the lower number of birds see above a mountain's tree line. Which of these factors is abiotic?

a.) high-flying predators

b.) limited food

c.) frequent high winds

d.) no trees for shelter