第二章单元测试
- How many types of bacteria can be found in a spoonful of good soil?（ ）
- How many soil layers typically make up mature soil?（ ）
- What role does soil play in the carbon cycle?（ ）
- What percentage of soil is made up of pores?（ ）
- What are the three principal characteristics of light that affect plant growth? （ ）
A:75,000 B:750,000 C:7,500 D:7,500,000
答案:75,000
A:2 B:3 C:1 D:4
答案:3
A:Important carbon storage B:Strengthening carbon sinks C:Important energy source D:Important water resource
答案:Important carbon storage
A:50% B:10% C:25% D:75%
答案:50%
A:Intensity, color, and frequency B:Concentration, spectrum, and time C:Brightness, wavelength, and period D:Quantity, quality, and duration
答案:Quantity, quality, and duration
