Earth's interior at a depth of 3500 kilometers is believed to be 1 - liquid at a temperature of approximately 4900
2 - solid at a temperature of approximately 4900
3 - liquid at a temperature of approximately 5400
4 - solid at a temperature of approximately 5400

It is d, all the other ones say incorrect answer .

Independent variable is something that is changed in a experiment. 

Answerthe valence of an element or radical is equal to the number of positive or negative charges on the ion.

Answer: 1.4 seconds which is the third optionexplanation: current is defined as the flow of charge per timetherefore, the equation that relates current, charge and time can be expressed as follows: i = δq / δtwhere: i is the current given = 1.8 ampereδq is the charge given = 2.5 coulombδt is the time required for the flow of the given charges to give the 1.8 ampere.substitute with the givens in the above equation to get the time as follows: 1.8 = 2.5 / δtδt = 2.5 / 1.8 = 1.38888 which is approximately 1.4 secondshope this was !