Answer AND Explanation:
<u>FACTORS THAT CAUSE GENETIC VARIATIONS</u>
- Crossing over. At the chiasmata during prophase I of meiosis, breakage may occur and exchange of genetic information may take place. New gene combinations which result in variations.
- Independent assortment. The arrangement of homologous chromosomes at the equator of the spindle during metaphase of the first meiotic division is random. These homologous chromosomes segregate into different daughter cells which contain different genetic combinations which brings about variation
- Fertilisation permits parental genes to be brought together in different combinations. This is the cause of variations in members of the same family.
- Mutation is the spontaneous change in the genetic makeup of an organism. These changes may be inherited by the offspring therefore beginning variation.
 
        
             
        
        
        
<span> - </span><span>A typical meal contains </span>all four<span> types of </span>macromolecules<span>. </span>Living things<span> are made of </span>four<span>types of molecules, known as </span>macromolecules<span>: ... Highly specialized at what </span>they<span> do, proteins form both the railways and the motors that ... it exists as a single strand and </span>has<span> a special building block not</span>found<span> in DNA.</span>
        
                    
             
        
        
        
Answer:
 - "Mid oceanic ridge"
 - "Mid oceanic ridge" 
Explanation:  
<em> Mid-ocean ridges are formed by divergent plate boundaries in the ocean. This is where upwelling magma creates new seabed. A diverging plate boundary occurs when two plates move away from one other. Magma rises from deep beneath the Earth and erupts along these boundaries, forming new crust on the lithosphere. The majority of divergent plate borders are undersea, forming submerged mountain ranges known as oceanic spreading ridges. </em>
Hope this helps! :D 

 
        
             
        
        
        
Answer:
Option (3)
Explanation:
The continental crust is usually thick because it has an average thickness of about 35-40 km. In the high mountain ranges, it is the thickest, forming about 80 km on an average. These are formed when two continental plates form a sandwich pattern by sharing a convergent type of plate boundary.
For example, the thickest part of the crust is the Mt. Everest which lies in the great Himalayan range, which has started to form about 50 million years back. It is geologically the most recent mountain range.
The older mountains are continuously eroded in the geological past, as a result of which the height of the mountains is affected.
Thus, the correct answer is option (3).