Hi There!
Biotic factors are all the living things in an ecosystem, and abiotic factors are all of the non-living things in an ecosystem. So, they differ because they both mean opposite things.
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Answer:
Explanation:
Given
mass of crane 
distance moved 
Since it is moving with a constant velocity therefore net force on it is zero
Tension force=weight
T=mg
Work done by Tension T is



Work done by Gravity will be equal in magnitude but opposite in sign and can be obtained by work energy theorem which states that change in kinetic energy of object is equal to work done by all the forces


Answer:
no
Explanation:
Platinum is a noble metal. The concentrations of platinum in the soil, water and air are very minimal. ... Finally, a danger of platinum is that it can cause potentiation of the toxicity of other dangerous chemicals in the human body, such as selenium.
Answer A is incorrect
A crest is just one point. It is not the distance between 2 crests.
B is incorrect
A trough is just 1 point. It is not the distance between 2 troughs.
C is incorrect.
the amplitude measures the height of a crest from the middle of the wave to the crest (or trough).
D is the correct answer. That is the distance between 2 crests or 2 troughs