Because, substances can pass through it while others can not but Oxygen, good molecules,
and waste products can only go through it.
Answer:
1In a hypothetical food chain consisting of grass, grasshoppers, sparrows, and hawks, the grasshoppers areprimary consumers. primary producers
Explanation:
a large group of plants that are defined as those land plants that have lignified tissues for conducting water and minerals throughout the plant
To establish causation sociology, there are three key factors namely correlation, time order and ruling out alternative explanations. correlation gives the difference between the alternatives to be considered, time order gives the occurrence of events chronologically, finally, the ruling out alternative explanation gives one the chance to get the best alternative
