Answer:
a. The substance is from an animal source.
Explanation:
Glycogen is a carbohydrate polymer in which animals store their excess glucose as. When animals digest their ingested food, it gets broken down into GLUCOSE. This glucose, when in excess, gets stored as GLYCOGEN. 
According to this question, a substance found at a crime scene is being examined using chemical tests. The test revealed that glycogen is present in the substance. This can mean that the substance is from an ANIMAL source because GLYCOGEN is only present in animals.
 
        
                    
             
        
        
        
Answer:
DNA polymerase proofreading
Explanation:
Proofreading by DNA polymerase corrects errors during replication. Some errors are not corrected during replication, but are instead corrected after replication is completed; this type of repair is known as mismatch repair.
 
        
             
        
        
        
The deserts are actually one of the most common and widespread landscapes on the planet Earth. The deserts, combined of all types, are covering around 33% of the landmass, thus one third of the whole landmass on the planet.
These multiple types of deserts, like the hot and dry desert type, cold desert, coastal desert, semiarid desert. All of them have their own unique characteristics that define them more specifically. The hot and dry deserts are the ones that are hot throughout all of the year, also being located deeper into the mainland. The cold deserts are found in the Northern Hemisphere, they have hot summers and very cold winters. The coastal deserts are located along the coasts, so despite being very dry, they do tend to have high humidity. The semiarid deserts are deserts that are not as dry as the other types, they receive more rainfall, though that happens just in few days of the year, so they are dry for the most of it again, with the biggest difference being that they have slightly more vegetation.