When looking across the periodic table from left to right, which of these groups are the first to contain nonmetals? group 2
group 7
group 14
group 18

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.

What is the mass of phosphorous in a 51-kg person

When did stem cell research become known ? who discovered stem cell? what experiments or studies have been conducted so far?