Answer:
they are made to work together and there ae different types
Explanation:
there just made like that
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
Important factor defining the desert biomes is its tendency to lose water by evaporation, and this potential for water loss exceeds the annual rainfall and defines what organism can live in there.
The answer is B. fight disease