Which of the Following is a Characteristic of All Angiosperms

Question

Which of the following is a characteristic of all angiosperms?
A)complete reliance on wind as the pollinating agent
B)double internal fertilization
C)free-living gametophytes
D)carpels that contain microsporangia
E)ovules that are not contained within ovaries

Accepted Answer

Double internal fertilization, where one sperm fertilizes the egg to form the zygote and the other sperm fertilizes the polar nuclei to form endosperm, is a unique characteristic of all angiosperms. The other options are not true for all angiosperms - some are pollinated by animals instead of wind, the gametophytes may not be free-living in all cases, carpels do not contain microsporangia but instead contain megasporangia, and ovules are typically enclosed within ovaries.