Fill in the blanks.
12. the basic units of structure and function in living things
13. a( a group of similar cells that perform a specific function in an organism.
14. nerve cells that carry response information to muscles and organs.
15. carbon dioxide are outputs of cellular respiration.
16. essential to living things because many of the chemical reactions that occur in living things require it.
17. scientists did not discover the cell until was invented because cells are too small to see without one.

The image shows a sandstone formation with visible bands of different colors. what do the bands indicate about how this sedimentary rock was formed? choose two answers. a). the rock was made from more than one material. b). water was absent during the compaction and cementation process. c). sediments and other matter were deposited in layers before lithification. d). the rock was stretched horizontally by the pressure from surrounding rocks. e). layers of hot liquid in the rocks cooled and solidified at different tempatures