<u>Answer:</u> The correct answer is 0.745 km
<u>Explanation:</u>
We are given:
A numerical value of 815 yards
To convert this into kilometers, we use the conversion factor:
1 km = 1093.6 yards
Converting the given value into kilometers, we get:

Hence, the correct answer is 0.745 km
Paramecia have a micro nuclei and a macro nuclei.
The largest atomic radius has Ba,because they are all metals of 2nd group,but as you know when you go down upright in the periodic table the metallic features getting stronger but also orbital layers increasing,and you can say more layers larger atomic radius.Hope I helped,sorry for English