D interceptive is correct
<span>Actually the developing offspring in the eight week of pregnancy is medically know as a fetus,Where the lungs of the baby are nearly developed, and baby continues to grow and mature, then reflexes of work starts woking slowly, after which baby prepares itself for delivery in next few days.</span>
The concept would be crystallization. As magma cools inside or outside of the earth it crystallizes into an igneous rock. Intrusive (formed inside crust) igneous rocks are typically more course grained and contain many different noticeable minerals (for example, granite). Extrusive (formed outside) igneous rocks are typically more porous and are more fine grained then intrusive rocks (example, obsidian).
Because it allows them to breathe and function.