<span>A prokaryote is a unicellular organism that belongs to either the domain Bacteria or the domain Archaea. Therefore, unlike a eukaryote, the prokaryote lacks in a nucleus and other organelles. The first organisms that appeared about 3.5 billions years ago were prokaryotes. They developed primitive forms of photosynthesis without oxygen as a waste. The first photosynthesizing prokaryotes appeared about 2.7 billion years ago which led to the changes in Earth atmosphere and consequently organisms dependant on oxygen could arise.</span>
Answer:
Option 4 - Calcium
Explanation:
The <em>divalent cation </em>called <em>calcium</em> is needed to provide additional support to the bone matrix.
Calcium is considered one of the most <em>important components</em> in bone development. It helps in the formation as well as maintenance of bone. During the modeling and remodeling process of bones, calcium facilitates the formation of <em>semi-hard new tissues</em> which leads to the formation of new bone which is very hard.
Due to this reason, calcium is needed to create extra bone matrix support.
