Estuaries may be either brackish or freshwater systems. true false 2. estuaries, much like wetlands, are breeding ground for many marine species as well as water fowl. true false 3. the biggest threat to the health of our estuaries is the erosion due to the constant movement of water, either tides, sea level flux, or currents. direct and indirect activities of man that contribute to pollution and deposition of sediments.

Ascience research group is testing a new type of plant food. one trial is conducted in a controlled experiment. the data from the trial show that the plant that received the new food grew faster than the control plant. the group announces that the new plant food makes plants grow faster. what is the main weakness in this scientific claim?

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.

Under which of the following circumstances would natural selection not operate on an organism