Which of the following is a part of an observational study?
a)control of all variables
b)manipulation of participants
c)collection of data
d)inclusion of bias

Which two criteria must be met before scientist can use radiocarbon dating? explain your answer

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.

The diagram shows the development of the oocyte and the follicle during the menstrual cycle. identify at which stage in the cycle the hormone levels are at their highest and most active.