답변을 얻은 뒤 반드시 감사의 덧글을 남기고, 좋은 답변은 채택해 주시는 센스...
질문할 때 예의를 지키시기 바랍니다.(빨리... 고수분만..... 이런 식의 요구는 자제 바랍니다.)
질문 내용 : 1. The ground at tundra is frozen for hundreds of meters in most spots, but warms enough in thesummer for the thin surface soil to melt and allow tiny plants to grow.2. The short ultrasound wave-lengths enable bats to located exactly even very small moving objects,such as mosquito-sized insects.