I believe the answer is B, Two humans with different eye color.
Answer:
D. reproduction
Explanation:
If the species doesn't reproduce they die out or become extinct.
Certain types of rocks form deep inside earth:)
The first one is second succession. The second question I don't understand.
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Answer:</u></h2>
<u>cardic muscles:</u> are present only in the heart .single cell is not very strong by itself, millions of cardiac muscle cells working together are easily able to pump all of the blood in the body through the heart in less than a minute. Cardiac muscle cells have a branched shape so that each cell is in contact with three of four other cardiac muscle cells.
<u>characteristics of cardic muscles: </u> one nucleus ,striated, involuntary, branched and joined to one another by intercalated discs that contain gap junctions for depolarization between cells and hold the fibers together when the heart contracts.
