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Stem cells are cells in the human body that have the ability to develop into many other body cell types. Stem cells are very useful for drug development, research, they aren't likely to be rejected in transplants, and are used to repair damaged or diseased cells and tissues. However, they cannot be grown for long periods of time, there are very small numbers in each tissue and cell making them very hard to find, and for certain studies they have been shown to cause cancer. To be honest, using them in research does have its pros and cons, they are very useful and easier to use in research, plus they can help repair damaged and diseased cell tissues. But at the same time they can be difficult to use correctly and properly, it can cause serious health problems if cancer doesn't take place. I think that using them in research is okay, as long as they are used correctly and properly.
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First of all, sex is a type of sexual reproduction. It’s meiosis. In meiosis, it has different stages and one of those stages is called Prophase 1. In prophase 1, genetic variation occurs.
        
                    
             
        
        
        
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i'm like 100% positive its answer  A
Explanation:
 
        
                    
             
        
        
        
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray Group 2 alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.[5] Free calcium metal is too reactive to occur in nature. Calcium is produced in supernova nucleosynthesis.
        
             
        
        
        
I’m on that same question