When Sarah performed this experiment, she changed the levels of nitrogen in order to observe the changes in the morphological features of the plant.
All of the characteristics of the plant that she observed were dependent on multiple different things, but the level of nitrogen was an independent variable that she was changing at her will.
Answer:
D. mixture
Explanation:
because the mixture is not part of an atom
Option - food is the correct answer.
Food vessels such as fu, gui, and dui were popular in Zhou times. These disappeared during the Han dynasty, during which the ding, zhong, hu, and fang were the main vessel types used. In Western and Eastern Han, the ding was one of the most common bronze-derived shapes in pottery.
