Answer: A
Explanation: It makes the most sense because it isn't directly speaking about something, it is mainly summarizing the main idea. I'm not 100%, but that's the one I would choose if it were me. Hope I helped out a little!
The Earth's layers in order from the center to the surface would be The Inner Core, The Outer Core, The Mantle, The Asthenosphere, The Lithosphere, then The Crust. Hope this helped!
-TTL
Just as the organs in an organ system work together to accomplish their task, so the different organ systems also cooperate to keep the body running. For example, the respiratory system and the circulatory system work closely together to deliver oxygen to cells and to get rid of the carbon dioxide the cells produce.
The last one...the species is unable to reproduce in any habitat beyond a population of 300 individuals
D. Certain genes are turned on and others are turned off; this action produces adult cells that are specialized
