Which statement is true of a placenta?
a. the placenta passes oxygen, nutrients, and other useful substances from the fetus to the mother.
b. the placenta passes oxygen, nutrients, and other useful substances from the mother to the fetus.
c. the placenta mixes blood from the mother and fetus together.
d. the placenta protects the mother from being attacked by the fetal immune system.

Cold case files recently began re-investigating an old murder case. the murder took place in the park; a young man, james, was hit over the head with a brick and killed. police suspected the jealous former boyfriend of james' wife, karen. whoever killed james may have washed their hands in a near-by bird bath as detectives found blood in the bird bath. since the murder took place before dna fingerprinting was available, the suspected killer, ronnie, went free. detectives are now reviewing the blood evidence using dna fingerprinting. based on the dna fingerprints of all possible suspects, who is james' killer?

What are the three different shapes or structures shapes or structure of carbon-based molecules?

What are ways that ordinary people can to keep antibiotic resistance from getting worse?