Answer:
The phenotypic ratios are the ratios of visible characteristics. The genotypic ratios are the ratios of gene combinations in the offspring, and these are not always distinguishable in the phenotypes.
Answer:

Step-by-step explanation:
We can solve this system just by summing each side of the equation:
So, both left sides will be sum, and both right sides too.
The resulting expression will be:

Ordering and solving both sides:

Hence, the value to the system is 
It's important to combine both equation, because the exercise is asking for the solution of the system.
Answer:
d. 60k
Step-by-step explanation:
The sample mean is the midpoint between the lower and the upper limit of the confidence interval, that is, the sum of the lower and the upper limit divided by 2.
In this problem, we have that:
Lower limit: 50k
Upper limit: 70k
(50k + 70k)/2 = 60k
So the correct answer is:
d. 60k
If you're asking if you can subtract this, for example:
x³ - x²
No. They must have the same exponent to be compatible. For example:
4x² - x² = 3x²