I would say it would be a. It makes the most sense
Answer:
The answer is D.
Explanation:
Silver consists of 92.5% silver, and the remaining part is copper. ... Pure silver is not susceptible to tarnish in a pure oxygen environment. However, the copper that is contained in 925 sterling silver may react to the ozone and hydrogen sulfide in the air and cause sterling silver to tarnish.
<span>Involuntary Muscles
</span>⇒ Involuntary Muscles <span>are muscles that contract without any conscious control.
The most important </span><span>Involuntary Muscle in the body is the heart. </span>
Mendeleev left gaps in the periodic table because, in the future, he knew that there would be more elements to be discovered because not all elements were discovered at the time.