REMEMBER: color blindness is carried on the X chromosome only! The male has to inherit the mutated gene from his mom and her X chromosome to be color blind. Because the male has only 1 X, he has a greater chance to be color blind than a daughter who would have to inherit a bad X chromosome from each parent!
If you follow the family tree, the person 12 (the daughter of 4x5) could be either XX or XX (I'm using bold to indicate the color blind gene on the X chromosome). You cannot tell from this family tree what she is (except that we know her mom (4) is definitely a carrier!
So you need to do two potential crosses:
1. Daughter 12 is not a carrier; so she is XX
Cross XX with XY; you get the possibility of all daughters as carriers XX, or all normal sons XY.
2. Daughter 12 is a carrier; so she is XX
Cross XX with XY; you get the possibility of daughters that are color blind (XX), daughters as carriers (XX), color blind sons (XY) and normal sons.
Answer:
In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. The theory of evolution is based on the idea that all species? are related and gradually change over time.
Explanation:
Planting the same crop in the same place each year zaps nutrients from the earth and leaves soil weak and unable to support healthy plant growth. Because soil structure and quality is so poor, farmers are forced to use chemical fertilizers to encourage plant growth and fruit production.