What is the atomic mass of an atom
with 20 electrons

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere,b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify,d)anaerobic bacteria kept thriving with more oxygen

Refer to the family pedigree shown here. in generation i, one parent is affected by the gene mutation and one parent isn't. in generation ii, all three children are affected by the gene mutation. what can you conclude about this gene mutation? a. all children born in future generations will be affected by this disorder. b. this gene mutation is a dominant disorder. c. this gene mutation is a recessive disorder. d. the generation i mother is a carrier of this gene mutation.