Explain why it is necessary to have a control group in a well-designed scientific experiment?

Study the following diagram and then answer the following question. Which channels are open during the A phase in the diagram?

I’d like to gather some feedback on different elements of this online course.  The official course evaluations you might have completed do not give me information about specific learning activities and whether or not they work for you – so please answer just a couple of quick questions to help me make this course better in the future. The discussion posts helped me to improve my writing and connect course content to real life issues in science.

Study the diagram and then answer the following question.   Identify the accumulation depicted in this diagram that leads to neuron cell death.  

Study the diagram and answer the following question:   What is the name of the space between the two neurons (highlighted in yellow)?

Which life style factors can benefit the aging brain?

Study the diagram and then answer the following question.   What phase of cell division does this diagram best represent?

In the diagram, three atoms are shown, each has the same number of protons but a different number of neutrons.  What are these atoms called?  

Explain why it is necessary to have a control group in a well-designed scientific experiment?

What type of bond is depicted in the image?