The swimming pools pH is below 7, meaning it is slightly acidic. If you want to make the pH higher, you must add a base which by definition has a pH higher than 7.
D. Add base
The third option because the elements mentioned in that selection are in the same group, they must have similar properties.
Answer:
They all wear their skeletons on the outside! This is called an exoskeleton and all creatures that have their structure on the outside are included in the phylum of Arthropods.
Explanation:
<>"One such trend is closely linked to atomic radii -- ionic radii. Neutral atoms tend to increase in size down a group and decrease across a period. When a neutral atom gains or loses an electron, creating an anion or cation, the atom's radius increases or decreases, respectively."<>
Complex meaning more complicated and detailed in difficulty
