Carbon dioxide
carbon monoxide
sulfer dioxide
It seems that you have missed the necessary options for us to answer this question so I had to look for it. Anyway, here is the answer. Varicose veins seen in the superficial veins of the legs are unsightly and often treated by surgically removing them. however, even without these veins being present, the return of all blood toward the heart from the legs is not diminished primarily because <span>blood can still return via the deep veins. Hope this helps.</span>
Answer:
A. Ancient bacteria
Explanation:
From the salt of the earth, researchers have isolated and revived a Bacillus strain, which they believe is >250 million years old. If correct, Russell Vreeland and his colleagues from West Chester University, Pennsylvania, have discovered the oldest living organism in the world.
Activation of muscle contraction could be a speedy event that's initiated by electrical activity within the surface membrane and transversal (T) tubules. This can be followed by unharness of metal<span> from the inner membrane system, the sarcoplasmic reticulum.
</span>Nervous stimulation causes a depolarization<span> of the muscle membrane (sarcolemma) </span>that<span> triggers </span>the discharge<span> of </span>calcium<span> ions from the sarcoplasmic reticulum.</span>
The stomach breaks down food , so it has the most acidic substance
