The correct answer is - the variable.
With the experiment, in the way that Dan had decided to perform it, the fertilizer is the variable, as in one of the parts with strawberries he uses fertilizer, while in the other part he doesn't uses fertilizer.
While this kind of experiment may give Dan some answers, and he might notice differences, still he would have to be more detailed in the experiment to see for sure if the fertilizer is the thing that makes some of the strawberries grow better than the others.
Dan should also put all of the strawberries at places that would receive the same amount of light, experience the same weather conditions, receive the same amount of water, and to be planted in a soil of the same quality. Only like this, after putting the fertilizer, Dan can now if it makes any changes or not.
 
        
             
        
        
        
Answer:
The correct order of events is:
C) Nicotine binds to the transmembrane protein that normally binds the neurotransmitter acetylcholine.
A) The acetylcholine receptor is an ion channel, and when a ligand binds, the ion channel opens.
B) An influx of ions carries the signal to the reward areas of the brain.
D) The signal causes release of dopamine in the brain, which causes good feelings.
E) Nicotine is quickly eliminated from the body (causing cravings for more cigarettes to produce good feelings).
Explanation:
Nicotine acts on acetyl cholinergic receptors that are located in membranes of the midbrain neurons. Nicotine can activate those receptors or block them more efficiently than acetylcholine.   Stimulation of nicotinic receptors leads to an increase in ions flow that reaches the brain and causes dopamine release in the nucleus accumbens through axonal prolongations of the dopaminergic pathway. This response is responsible for the smoker´s recompense sensation.
The dopaminergic pathway is the most important way in the process of nicotine dependence and addiction to the drug.  
 
        
             
        
        
        
Answer:
a. Karyotype
Explanation:
Karyotypes describe the chromosome count of an organism, so all the chromosomes would be in front of you, and it'd be easy to tell if there are 2 or 3 chromosome 21.
 
        
             
        
        
        
Answer:
At the second stage the cell differentiation is start.
 
        
                    
             
        
        
        
I would say "false" or the second option. Satan was still a angel he just tricks Adam and Eve into doing the one thing God asked them not too and then God cast Adam, and Eve out and Satan became Satan. Which means that the tempter caused the fall of man while he was still a angel.
Hope this helps.