False 
crossing over occurs in prophase 1 of meiosis 1. The significance of this crossing over is to ensure cell differentiation. If this occurred in prophase two it means the cells in meiosis 1 will be identical.
        
                    
             
        
        
        
Answer:
A biome is described as an area of the planet, which is classified on the basis of plants and animals living in that area. Soil, amount of light, temperature, and water are some of the important factors that determine what type of life exists in a biome.
The temperature, vegetation, and precipitation are the important characteristics of the biome.
Examples of biomes include tundra, desert etc.
 
        
             
        
        
        
Answer: Combining a basic API with citric acid to produce the citrate salt of the API.
Explanation:
Chemical modifications refers to the processes that involve changes in the general composition of drugs to produce another entity with different chemical properties. 
From the answer, Basic API combine with citric acid to produce the citrate salt of API which have different chemical properties from the reactants.
 
        
             
        
        
        
Answer:
The correct answer is option - e. all of the above are useful traits.
Explanation:
A cloning vector is a small segment of DNA that can be established stably in an individual organism and able to internalize a foreign DNA for cloning purposes. The cloning vector could be taken from different organisms such as plasmid of a bacterium, or DNA from a virus. A cloning vector must possess some characteristics -  
The cloning vector must be self-replicating ability in the host cells, it should be small in size with restriction site for the restriction endonuclease enzymes in it. The replication character of the vector should not interfere with the internalized DNA fragment. The presence of marker genes in the vector is also a property that is helpful in identifying of recombinant cells.
Thus, the correct answer is option - e. all of the above are useful traits.
 
        
             
        
        
        
The correct answer is A. An infection that migrates via the bloodstream
Explanation:
Osteomyelitis is a serious condition, in which an infection develops in bones. This causes symptoms such as pain, inflammation, and can lead to the spread of the infection to other tissues or bone necrosis if it is not treated. In terms of causes, this condition develops when the bone is exposed to bacteria or similar that causes the infection, this can occur during surgeries or fractures. However, the most common source of infection is via bloodstream this means the bacteria or germ is in the blood and it enters the bone through the bloodstream. Also, once the bacteria or germ is in the bone it causes the infection.