B. One
because an independent variable is something you change. So in a scientific experiment you only change one thing. If you happen to change more than one thing then the test becomes unfair therefore you should repeat and make sure that only one thing is changed this time.
Answer:
The atmosphere is a closed system
Explanation:
Because inside the atmosphere open system
Answer:
Photosynthesis doesn't occur at night. When there is no photosynthesis, there is a net release of carbon dioxide and a net uptake of oxygen. ... the rate of photosynthesis is higher than the rate of respiration. there is a net release of oxygen and a net uptake of carbon dioxide.
Answer: Transcription - A
Explanation:
This problem is talking about the lac operon and the gene expression of lac operon. If the gene is turned off, then transcription, the generation of mRNA won't occur.
The main function of the nephron is to filter wastes out of the body and the re-absorption of substances required by the body.
The nephron also has components that have specific functions. There are about 1 million nephrons in one kidney