How many neutrons does element x have if its atomic number is 39 and its mass number is 84?

Identify the various levels of atmosphere. troposphere mesosphere exosphere stratosphere thermosphere

Which way do the nitrogenous bases in dna pair up? a. a and g; t and c b. a and c; t and g c. a and t; g and c d. a and a; t and t; g and g; c and c

The rapid decomposition of organic matter produces evidence which supports: the slow accumulation of coal deposits long ages of the earth rapid burial of vast amounts of vegetation biblical account of noah's flood