Propofol lowers the resting membrane potential of neurons by opening an ion channel, causing a(n)

The neurotransmitter in the prior question binds to which type of receptor?

Volcanoes release a variety of gases to the Earth’s atmosphere, some desirable, some not.  Which of the following is the most abundant gas released by volcanism on Earth?

About how old is life on Earth, meaning about how old are the oldest fossil organisms or trace fossils that we know of today?

Where is the fastest flow in a river?

Which of the following is one of the two major drivers of surface tectonic plate motion?

Wegener put forward a number of different observations as support for his theory that landmasses had moved great distances on the surface of the globe.  Which of the following is not one of Wegener’s lines of evidence?

The concentration of oxygen in the atmosphere has been pretty much constant throughout Earth’s history?

What medium transports the most sediment on Earth’s surface?  Note: I’m not asking about capability, but rather amount.  One of the following accounts for the vast majority of sediment transport.  Which is it?

Where does most hydrothermal metamorphism take place?