My first thought would be to use the light in the sky for help. stars and moon as night and sun as day, you can tell by when the sun rises and moves.
<span>The cells all have different qualities.
A plant cell will have a cell wall (the others don't have these) and so it will be kept in a rigid shape, unlike the others which are free to be blobby. Inside a plant cell, there is also a vacuole containing cell sap. The others don't have this. Plant cells also have chloroplasts, which look similar to mitochondria on a diagram. Chloroplasts contain chlorophyll, and this is used for photosynthesis. </span><span>
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The organs that work together is called systems. It is a group of parts or organs that interact and work together for a common purpose or function. Each of the parts seems to depend to each other in order to achieve their shared functions and goals. When one of the organs in a system becomes dysfunctional, automatically the other parts cannot function as effective as they were during those times that everybody's in good condition becaus the condition of one organ in the system directly affects the others too.
Option B: differential reproduction
