The correct option would be c.
Answer:
Density is nearly 3 cabs per hectare
Explanation:
Given -
There are three three intertidal regions.
Area of each intertidal region is 
hectares.
Number of crab in the intertidal regions are as follows -
Intertidal region I - 7
Intertidal region I - 2
Intertidal region I - 6
Sum of crabs in all three regions is equal to
Total area of all three intertidal regions is equal to
hectares
Now density per hectare is equal to total population of crab divided by total area of all the three intertidal regions
Density 
Density is nearly 3 cabs per hectare
To know what happens here, you need to analyze the alleles.
If the father is color blind and the daughter is not, you can suppose that is a recessive allele.
You can tell she is a carrier only, and because we received one sexual allele from each parent. If they ask you about the gender, we can suppose a cross between Xx and XY being lower x the recessive allele (color-blind vision).
When you draw the Punnett square, you'll found the probabilities are XX, XY, Xx, and xY.
So, you have a 50% chance of having a boy and 25% chance of having a color-blind boy.
The reproductive system is different from other body systems in that the reproductive system functions in the survival of a species while all other body systems function to ensure the survival of the individual.
