Answer
Correct answer is :It has two elements
Explanation
A binary compound is a compound that is made up of two of the elements in the periodic table. Some examples of binary compounds are 
and 
. This means that a binary compound can have more than 2 atoms as in the case of hydrogen oxide. Some binary compounds are ionic as in the case of sodium chloride.This shows that they do not necessarily have to have covalent bonds. This also rules out the possibility that they may always have double bonds as ionic compounds are bound together by ionic bonds. The only thing that will always be true of binary compounds is that they will always have 2 elements.
B. the nervous system connects bones
Answer:
Here's three just in case. The three core principles of evolution – variation, heredity, and differential fitness – crystalized in the 1970s, still serve as a conceptual benchmark for the theory of evolution by natural selection.
Explanation:
The sentence probably saying about polyploid
Polyploid is when the cell duplicates a complete set of chromosome. This will result in one extra chromosome for each kind which makes them triploid, tetraploid or more. The polyploid organism will more likely to die. In the animal, the extra chromosome will cause sexual imbalance and can make it infertile.
Answer:
Skin
Explanation:
This is the largest organ of the body, including many functions.
