Which observation did researchers make in studies on separated twins ?

Depending on whether they where conjoined initially, or where born separately really changes the answer of this question. Although studies show that twins generally have a kinetic link, more practical research says that twins are 25% more likely to both be left handed, which is a recessive gene, they are also more likely to die in child birth, twins are more likely to understand and be biligual, along with many other advantages twins may have.

The charge of an ion with 55 protons and 52 electrons is +3. the reason is because protons are positive, and there are three more than the amount of negative electrons.