A Shortage of Dopamine. Parkinson's disease occurs when nerve cells, or neurons, in an area of the brain that controls movement become impaired and/or die. Normally, these neurons produce an important brain chemical known as dopamine, but when the neurons die or become impaired, they produce less dopamine.arkinson's disease occurs when nerve cells, or neurons, in an area of the brain that controls movement become impaired and/or die. Normally, these neurons produce an important brain chemical known as dopamine, but when the neurons die or become impaired, they produce less dopamine.
Weight density is not a term. Weight is the effect of gravity on a Mass and will be less on the Moon since the moon has less mass and therefore less gravity than the Earth.Density is mass/volume and since mass is constant, density would also be constant.aking the world better, one answer at a time. Weight density is not a term. Weight is the effect of gravity on a Mass and will be less on the Moon since the moon has less mass and therefore less gravity than the Earth. Density is mass/volume and since mass is constant, density would also be constant.
Before we look at all the different theories, we need to look at some of the differences and similarities between the Earth and Moon: The Earth has a large iron core, but the Moon does not. Earth has an average density of 5.5 g/cm 3 and the Moon has an average density of 3.3 g/cm 3 (because it is depleted in iron). The Moon has exactly the same oxygen isotope composition as the Earth, whereas Mars rocks, and meteorites from other parts of the Solar System (e.g. the asteroid belt) have much different isotope compositions.