How does the contractile vacuole in a paramecium help maintain homeostasis<span>? It pumps excess water out of the cell. ... Threadlike structures made of a protein called actin - it maintains cell shape, </span>help<span> build cilia and flagella, form centrioles in cell division.</span>
To separate each species into their own classes to better study them.
Answer: It is supported by hypotheses, repeated tests and law from one or more fields of science.
Explanation:
In the context of science, a theory is a well-established explanation for scientific data. Theories typically cannot be proven, but they can become established if they are tested by several different scientific investigators.
Lactose metabolism is regulated by lac operon in prokaryotic cells. When in the environment lactose is present, the cell signals the presence of lactose and synthesizes the enzyme required for the degradation of lactose. Removal of lactose from the environment leads to the termination of the enzyme synthesis. Thus, the metabolism of lactose is environment dependent.
The metabolism of lactose is also dependent on the presence of glucose. Glucose is the favorite food for bacteria. If glucose and lactose both are present in the environment, the bacterial cells prefer glucose over lactose and lactose is not metabolized. In the absence of glucose, the cells will metabolize lactose.
