<span>25%
   Starting from my First cousin family, I know for sure that the Uncle is is a carrier (Aa) and he must have married a wife who is also a carrier (Aa) and that is how they got an affected son. Thus, this leads to the fact that either both of my grandparents are carriers (Aa x Aa) or only one of them is a carrier (Aa x AA). As a result, the chances that my mom (who is related to the uncle who has a defected child) is a carrier is either (2/3 or 1/2) depending if my grandparents genotype, respectively. Thus, if my mom chances of being a carrier is 1/2 then my chance of being a carrier is 1/4. (given that my dad is not a carrier b/c CF is a rare disease) However, if my mom chance of being a carrier is 2/3 then my chance of being a carrier is (2/3)x(1/2)=(1/3) As a result, I could either be 1/4 or 1/3. But since the answer only provide the choice of 1/4 and not 1/3. This leave 25% is the correct answer.</span>
        
                    
             
        
        
        
Answer: After several days, a large bubble of gas collected in the upside-down beaker contains OXYGEN.
Explanation: 
Plants are known to be be autotrophic (producers) through the use of inorganic substance such as water, carbondioxide and light energy from sunlight in a process known as photosynthesis. 
An experiment was carried out by Latecia for investigation of the gas production of a water plant. It's therefore expected that OXYGEN gas which is the by-product given off during photosynthesis in green plants would be collected from the upside down beaker as gas bubbles.
 
        
             
        
        
        
Answer:
1.) The two gametes found in humans are the sperm and the ova. 
2.) Variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).
3.) Because the alleles that the mother and the father carry are mixed together in the offspring. 
4.) Because it only introduces genetic variation into the population if a random mutation in the organism's DNA is passed on to the offspring.
Please this is all I can answer