I say b and d because they both indicate about the heart
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Below are the choices that can be found from other sources:
<span>a. 10 electrons
b. 6 electrons
c. 12 electrons
d. 16 electrons
e. 8 electrons
</span>
Answer is 6 electrons. <span>The part with the two units of + charge is a cation; the part with the unit of - charge is an anion.</span>
The appearance of fossils would the the answer.
Although there has been some scientific debate about what fossil strata should mark the beginning of this period, the "International Geological Congress" determined that the Cambrian period was approximately 543 million years ago of which the first appearance in the fossil record of worms that made horizontal burrows was discovered.
