Place the following events of an action potential in the correct order. Na+ channels inactivate and voltage-gated (VG)K+ channels activate, allowing K+ to flow out of the axon, and repolarization begins. An unstimulated neuron has a negative resting membrane potential. The axolemma (the cell membrane of an axon) returns to resting membrane potential. VG Na+ channels open and Na+ enter the axon, causing a depolarization in this section of the axon. Local potentials accumulate to depolarize the membrane at the axon hillock.

Give the order in which antigen recognition by T cells occurs. (5points) Antigen fragments bind MHC. Antigen fragment in MHC is displayed on cell surface. MHC-peptide complex is transported to cell surface. Pathogen is taken in by, or infects, a host cell. Encounter with specific T-cell triggers immune response. Host cell enzymes make fragments from the antigen

Gas exchange in the lungs is due to 

During countercurrent exchange 

What is the direction of the magnetic field at the center( point P) of the square loop of current? Screen Shot 2022-08-11 at 2.16.28 PM.png 

In each element of a series LCR Circuit

A wire is carrying current vertically downward. What is the direction of the force on this wire due to Earth’s magnetic field?

You are standing on a sidewalk. There is a car in the distance. The horn on the car sounds. You hear it at a pitch that corresponds to a sound frequency lower than the frequency emitted by the horn. What can you conclude?

An electron moves with a speed of 5.0 × 10 4 m/s perpendicular to a uniform magnetic field of magnitude 0.20 T. What is the magnitude of the magnetic force on the electron? ( e = 1.60 × 10 -19 C)

A parallel plate capacitor initially has a voltage of 400 V and stays connected to the battery. If the plate spacing is now doubled, what happens?