What is a placenta? A. A ball of about 100 cells
B. A structure that nourishes the fetus
C. An unfertilized egg
D. Is sperm fused with an egg

1. which of the following is correct regarding opiates/opioids: a. they all have a natural component as a starting pointb. they have low addiction possibilitiesc. methadone binds to some of the same receptorsd. a and care correcte. all are correct

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

In an hydrogen ion pump the energy is used to join small molecules together to make larger ones which factor most likely has the greatest effect on the number of molecules mitochondria can produce