Many athletes use altitude training to improve their performance. They travel to areas of high altitude where there is less oxygen in the air. The body adapts to the stress of less oxygen by becoming more efficient at transporting and using oxygen. What are athletes who train in high altitudes most likely trying to enhance? energy production in the mitochondria

enhancement of the nervous system

pH balance of red blood cells

building of muscle tissue

Consider each of the electric- and magnetic-field orientations given next. in each case, what is the direction of propagation of the wave? a)\vec ein the +xdirection,\vec bin the +ydirection. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction b)\vec ein the -y direction,\vec bin the +x choose+ x direction- x direction+ y direction- y direction+ z direction- z direction c)\vec ein the +z direction,\vec bin the -x direction. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction d)\vec ein the +y direction,\vec bin the -z direction. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction