The answer to this question would be...
B. Thousands
If you go to webpage <span>http://www.shapeoflife.org/2d-animal-cells-have-many-thousands-genes it will give you the same answer if you read through it.
Hope this helps a lot, leave a rating and like if it did!</span>
Answer:
Most fish use gills for gas exchange instead of lungs.
Explanation:
If they are both carriers , we can create a cross with Rr.
The probability of not even carrying PKU is 1/4 or 25%
The probability of carrying is 2/4 or 50%
And the probability of inheriting the disease PKU is 1/4 , 25%