A.gold is the answer. As it's density is 19.32 grams per cubic centimeter which is lot more than the other substances.
Recessive genotype I hope this helps
Answer: the answer would be four thousand
Explanation: hope this helps
Work needed: 720 J
Explanation:
The work needed to stretch a spring is equal to the elastic potential energy stored in the spring when it is stretched, which is given by

where
k is the spring constant
x is the stretching of the spring from the equilibrium position
In this problem, we have
E = 90 J (work done to stretch the spring)
x = 0.2 m (stretching)
Therefore, the spring constant is

Now we can find what is the work done to stretch the spring by an additional 0.4 m, that means to a total displacement of
x = 0.2 + 0.4 = 0.6 m
Substituting,

Therefore, the additional work needed is

Learn more about work:
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Hope that helps, Good luck! (: