Those goods are available in strong wooden drums of 1,2,5,10 and 20 litres.
这些货物分别装入1、2、5、10、20升的木桶里。
It was not forced upon them by the survival competition; they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do.
毒液不是生存竞争强加给它们的,它们也可以不用毒液捕捉动物而生存,就像今天成千上万的无毒蛇那样。