单选题 It can be inferred from the passage that the decision to study an organism may sometimes be influenced by______.

A、 its practical or commercial benefits to society
B、 the nature and prevalence of its fossilized remains
C、 the relative convenience of its geographical distribution
D、 its similarity to one or more better known species

【正确答案】 A

【答案解析】由第一段中此句existing species are not well studied，partly because neither the animal’s fleshy inner tissue nor its shell has any commercial value可判断选项A正确。