<span>a)
</span>The milkweed is the primary producer in the
ecosystem. It manufactures food from the abiotic factors in the soil such as
nitrates and water and those in the atmosphere such as carbon-dioxide and
sunlight. The milk weed is then fed on by the caterpillar and a primary
consumer. The caterpillar is then fed on the mocking bird (secondary consumer)
<span>b)
</span>Increased human population growth and their activities
have resulted in the emission of carbon dioxide and other greenhouse gases in
the atmosphere. This has increased the global temperature. This increase of
global temperature increase ocean temperatures causing coral bleaching.
Another example is depletion of water sources
by human activities hence causing drought. Drought reduces the amount of
vegetation growth due to scarcity of water in the soil (due to lowering of the
water table) for plant growth.
Answer: 26.75 meters.
2πr = 84
2 * 3.14 * radius = 84
radius = 84/6.28
r= 13.375
So the diameter will be 13.375 + 13.375 which is 26.75 meters.
A force of 8 N will be required.
<h3><u>Explanation:</u></h3>
Mechanical advantage is defined as the ratio of output force from a system to the input force into the system. A machine which has the mechanical advantage more than 1 means it requires less force to give more force as output. Similarly, when the mechanical advantage for the machine is less than 1,it means more force is required to give to achieve a less one.
Here in the question, the mechanical advantage of the pulley is 2.
Output force required to pull the sack of potatoes upto kitchen is 16N.
Mechanical advantage = Output force / input force.
Or, 2= 16 / input force.
So input force = 
So a force of 8 N will be required to pull the pulley.
