<span>It is true that the first trimester is the most critical time for an embryo or a fetus. This is because there are many crucial developmental stages in this time period in order to produce a viable and functional multicellular organism. Such developmental characteristics in this period include the successful formation of the notochord, the basic nerve structures and the beating heart. It is critical for such structures and organs to form properly in order to ensure subsequent developments in the fetus to form correctly and ultimately result in a successful deliverance.</span>
A concussion, as found on Google, is a "temporary unconsciousness caused by a blow to the head.", which means a really hard hit to the head, and then a knock out or a blackout
Some symptoms that are usually associated with a concussion can be but are not limited to: headaches, memory loss (if severe), nausea, vomiting, slurred speech, confusion, and fatigue. There can also be sleep disturbances, sensitivity to any type of change, such as air or light, and disorders of the 5 senses (sound, sight, touch, smell, and taste).