Answer:
There are 8 electrons in the outer ring, and has to react with 8 or fewer electrons to form a stable molecule. 
Explanation:
The outer-most orbits of  silicon contains a maximum of eight (8) electrons. It requires 8 of fewer electrons to form a stable molecule. 
 
        
             
        
        
        
Answer: The blanks can be correctly filled up with prophase I and metaphase II.
Explanation:
In females, finite number of oocytes are present since birth. The process of oogenesis initiate in embryonic stage only. However, oogonia divide and mature to form primary oocytes. These primary oocytes start meiotic division but arrest in prophase I stage before birth.
After a girl attains puberty, one primary oocyte resumes its division each month during a menstrual cycle. The primary oocyte divides to form secondary oocyte and polar body.
Polar bodies degenerate after completing meiosis II. However, secondary oocyte halts its division again at metaphase II until fertilization takes place. Once fertilization takes place it completes its meiosis II and results into mature ovum and polar body.
 
        
             
        
        
        
So to sum up, when matter is transitioning from solid to liquid (melting) or liquid to solid (freezing<span>), its </span>temperature<span> is fixed at the </span>melting/freezing<span> point, which is the </span><span>same temperature</span>
        
             
        
        
        
Other biological molecules that contain the element of N would be nucleic acids such as DNA and or RNA. There are found in the nucleotides that constitute or make up these nucleic acids.
        
             
        
        
        
Approximately one billion oxygen molecules. that is because there are about 250 million molecules of haemoglobin in each cell, and each haemoglobin molecule binds to 4 oxygen molecules