Answer:
d. eon, era, period, epoch
Explanation:
The geological time scale has been made so that the scientists can have a practical system about the classification of geological time, thus everything that has happened throughout it. The geological time unites have been defined in accordance with important events that have happened, thus marking their end or beginning. These events can be mass extinctions, catastrophes, climate patterns, domination of certain species etc. The longest of these time units is the eon, lasting for more than half a billion years, and up to 2 billion years. The era comes as the second longest time unit, lasting for several hundred million years. The period lasts for several tens of million years, and the epoch is the smallest unit, lasting for few million years, or several hundred thousand years.
<h3>A. Cellulose </h3>
