It's B. Stimulants speed up the central nervous system.
Animal cells do have vacuoles although there is not a fixed amount of them. They are smaller than the large central vacuole in the plant cell and larger in number as well.
Answer:
1920s and 1930s,
Explanation:
it's worth reiterating that helmets were not mandatory. That wouldn't happen until 1943. During the 1920s and 1930s, variations of the leather helmet appeared, but in 1939, the game changed –or at least became safer– when John T. Riddel introduced the first plastic helmet
Answer:
Nomadic Bedouin tribes dominated the Arabian Peninsula before the rise of Islam. Family groups called clans formed larger tribal units, which reinforced family cooperation in the difficult living conditions on the Arabian peninsula and protected its members against other tribes.
Explanation:
