plant species that are well adapted to survival in dry climates are being looked at for an answer in developing more efficient crops to grow on marginally arable lands.
A. Pests
B. Gas
C. Bacteria
D. Insects
* Đáp án
B
* Hướng dẫn giải
Đáp án B Đ2: which can come from inorganic agents such as gases, or organic agents which include bacteria and plant pests. -> gases