What is most likely the reason the author included the information about "boom and bust" periods?

it would lead to upper respiratory infections and pneumonia.

answer: angiosperms

dicots

angiosperms are highly evolved plants, they produce seeds which are enclosed within in a carple. these are the largest group of plants on earth. they include trees, shrubs, herbs and small flowering plants. angiosperms exhibit a flowering stage in their life cycle. the flower serves the function of reproduction and fruit formation in majority of angiosperms. dicot is the term used to describe flowering plants that have two seed leaves. dicots are plants which develop seeds which split into two parts called cotyledons. each cotyledon contains one embryo.

here, a small purple flower development indicates that the plant belongs to angiosperms and having two embryonic leaves indicates it belongs to dicots.  

b. lithosphere, asthenosphere, mesosphere   is the answer most likely