The question of why prehistoric animals became extinct has not been conclusively answered.
Giải chi tiết:
Đáp án là D. conclusively = decisively : cuối cùng
Nghĩa các từ còn lại: predominantly : phần lớn là..; extensively: cách rộng rãi; especially : đặc biệt là ..
Biogas can be utilized for electricity production, cooking, space heating, water heating and process heating.
Population growth rates vary among regions and even among countries within the same region.
Around 150 B.C. the Greek astronomer Hipparchus developed a system to classify stars according to brightness.