(2013·四川省宜宾五校二调)A recent study has ________ an unexpected conclusion that the African elephant should be divided into two different species.

A．kept up with

B．made up with

C．caught up with

D．come up with

某课外活动小组利用烧瓶做了一个演示潜水艇原理的模型，通过胶管A从烧瓶吸气或向烧瓶吹气，就可以使模型下沉或上浮。如图所示，模型静止在水中，从烧瓶中吸气使其下沉时，烧瓶受到的浮力将________（选填“变大”、“变小”或“不变”）。