Birds that fly to the tundra to nest during the summer are said to be

Migratory

Bird migration is the conventional periodically movement, often north and south along a flyway, within breeding and wintering terrains. Many varieties of bird migrate. Migration carries high costs in extinction and mortality, from poaching by people, and is motivated essentially by the availability of food.

answer; i believe that the correct answer is(d) nondisjunction during meiosis;