If the ecosystem is balanced then the population would aslo be balanced, IG its the unbalanced ecosystem which leads to unbalanced population and when its unbalanced then we can say which one would be largest and which one smallest..
1. Rhythm generators (SA node)
2. Conductive cells (node cells)
3. Contractile cells (myocardial cells)
I believe it is B. Heterozygous; homozygous. The prefix hetero means two different and the prefix homo means two of the same