Answer:
Option B. 
Step-by-step explanation:
we know that
The frequency is equal to the number of cycles divided by the time
Remember that
1 cycle = 1 full wave to repeat itself
In this problem
From o to 12 seconds ------> there are 2 cycles
therefore
The frequency is equal to

Hi, do you have to picture?
um is the end a 3 and 2 or 32 or 3*2?
Answer:
The geography of China isolated it from other cultures because there were the Himalayan Mountains, the Tibet-Qinghai Plateau, the Taklimakan Desert, and the Gobi Desert