Mark all those of the following that are appropriate uses of glassware in the laboratory:

a. to accurately measure 20.00 +/- 0.02 ml, use a 10.00 ml pipet making two deliveries.
b. to accurately measure 20.00 +/- 0.02 ml, use a 150 ml beaker with marked graduations.
c. to quickly approximate 20 ml, use a 10.00 ml pipet making two deliveries.
d. to quickly approximate 20 ml, use a 150 ml beaker with marked graduations.

answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.