脂肪摄入不足会影响大脑发育，引起（）；脂肪储存过量会引起肥胖，增加心脏负担。

A、某些皮肤病（如湿疹）

B、营养不良，生长发育缓慢，免疫力下降

C、体重轻，易疲劳、头晕等

D、消化不良，便秘

Multipurpose Internet Mail Extension (MIME) is a (46) document messaging standard in the Internet enviroment, with MIME, users can send (47) Email messages that include audio, video, graph-ices, and text to any other user of a TCP/IP network. Richtext information can also be (48) into messages. It defines the fonts, formats, and (49) features of a document so the document can be easily (50) on many different types of systems.

（49）是（）

A.color

B.size

C.design

D.layout