Obstetric sonography is a technology that allows doctors and parents to see images of a fetus as it develops in a woman’s womb. this practice is commonly referred to as an ultrasound. generally, a woman will get two or three ultrasounds during her pregnancy. which is the most likely medical reason that a doctor might require a pregnant woman to get ultrasounds more frequently?
a. to predict the due dateb. to gather pictures for an albumc. to prepare for special medical needsd. to find out the gender of the baby

If scientists are wrong about earth's age based on radioactive material and the decay rates are really much faster, how would nuclear power plants be affected?

Casts and mold are a type of preservation where the original material decays, leaving a mold in surrounding rock that can be filled with another sediment a. true b. false

Female luna moths (actias luna) attract males by emitting chemical signals that spread through the air. a male hundreds of meters away can detect these molecules and fly toward their source. the sensory organs responsible for this behavior are the comblike antennae visible in the photograph shown here. each filament of an antenna is equipped with thousands of receptor cells that detect the sex attractant. based on what you learned in this chapter, propose a hypothesis to account for the ability of the male moth to detect a specific molecule in the presence of many other molecules in the air. what predictions does your hypothesis make? design an experiment to test one of these predictions.