Answer:
DNA is the genetic material of all the living organism except some viruses. The structure and the characteristics of the DNA was well explained by Watson and Crick.
DNA is a double stranded molecule in which nitrogenous bases are linked together. Watson and crick explained that DNA strand are antiparallel. The antiparallel nature of the strand means one DNA gas a polarity of 5' to 3' direction whereas the another strand of the DNA gas polarity of 3' to 5' direction. These two strands has opposite polarity and runs in anti parallel directions. Thus, the DNA strand known as antiparallel strands.
 
        
             
        
        
        
Answer: The drive theory of motivation.
Explanation:
The drive threory of motivation is based on the principle that organisms have certain psycological or physiological needs (in this case, hunger). When those needs are not satisfied, a tension in the organism is produced, and with it a drive to seek the satisfaction of that need. 
Because the substance the rat recieves is nonnutritive (it doesn't reduce the rat's hunger), we can clearly see that the rat isn't performing the response because of this drive, seeking for the satisfaction of its hunger, but is motivated by another feeling. Therefore, this observation is problematic for the drive theory of motivation.
 
        
             
        
        
        
The answer to this question would be hydrolysis
There is amylase enzyme inside saliva that will break down starch into maltose sugar. Maltose is the sugar that <span>causing </span>the sweet sensation in the tongue. Since it will take for the reaction to happen, the sweet taste only appears after a few moments after you chewing the bread.
The reaction that was catalyzed by amylase is hydrolysis.
        
             
        
        
        
Answer: the mantle B
Explanation: Largest layer resulting in biggest mass.