What do the crescent moon-shaped dumplings (水饺shuǐjiǎo) represent?

When should 水饺 not be replaced with any other delicacy?

How long is the history of grain processing in China? Please answer in English.

What has become the most popular crop in Northern China over the past 4,000 years? Please answer in English.

What is a staple food?

A staple food, sometimes simply referred to as a staple, is a food that is eaten routinely and in such quantities that it constitutes a dominant portion of a standard diet in a given population, supplying a large fraction of the needs for energy-rich materials and generally a significant proportion of the intake of other nutrients as well. (Wikipedia - http://en.wikipedia.org/wiki/Staple_food)

Question:

What is the word for "staple food" in Chinese?

• Please input the Chinese characters first followed by a space and then the pinyin.
• Please write numbers for the pinyin tones, e.g. zhong1guo2

Qishan Saozi (hot / sour and spicy) noodles are made with five different coloured ingredients. They are red,  yellow, green, white and black.  What do the ingredients in the hot / sour and spice noodles represent for the people of Qishan?

According to the program, what percentage of the population in China is rice staple food for? 

老师的电话是82304156。

我昨天上午去商店买苹果了。

男的没看见张先生。