Intercalated disks support the synchronized contraction of cardiac muscles
These structures are known as Ribosomes.
Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.
D is the correct answer :).
The four inner planets have slower orbits, slower spin, no rings, and they are made of rock and metal. The four outer planets have faster orbits and spins, a composition of gases and liquids, numerous moons, and rings. The outer planets are made of hydrogen and helium, so they are called gas giants.
