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
Answer:
Umm...I'm not sure if this is a question where there is MC but if not, the the answer would most likely be, "By actually doing then saying"
Explanation:
Answer:
Magnification can be calculated using a scale bar. ... Magnification = scale bar image divided by actual scale bar length (written on the scale bar).