题目内容:
Whydoresearchersestimateelephantnumbersinanareabycountingdungpiles?
A.Becauseelephantsaredifficulttocatch B.Becauseitisnotpossibletocountelephantsfromaplan
C.Becauseitisnotpossibletokeeptrackofelephant
D.Becauseelephantsareshyanimals
参考答案:
答案解析: