Answer:
b
Explanation: the server serves for an entire game until they switch to the opponents serving.
Answer:
1. spontaneously
2. resting potential
3. action potentials
4. pacemaker potentials
5. K+
6. Na+
7. into
8. Ca+
Explanation:
Pacemaker cells (also known as sinoatrial node cells) are cells that generate rhythmic impulses and set the pace for blood pumping in the heart. These cells have the ability to rhythmically depolarize and initiate action potentials. In pacemaker cells, Ca2+ and Na+ levels are higher in the extracellular environment, while K+ concentration is higher intracellularly. The pacemaker action potentials have three phases: 1-depolarization, where membrane potential reaches -40 mV and voltage-gated Ca2+ channels open, 2-repolarization, where voltage-gated Ca2+ channels close and voltage-gated K+ channels open, and finally 3-gradual depolarization, which is caused by the slow influx of Na+ ions.
Answer:
Alternative schools provide educational options for students who are not successful in typical schools. Over the years, they have been viewed as schools where "bad kids" go, but that's not necessarily the case. Many students in alternative schools do not have behavioral problems.
Explanation:
Alternative schools have been established since about the 1970s to meet the needs of children and adolescents who cannot learn effectively in a traditional school environment (i.e., conventional public or parochial schools) due to learning disabilities, certain medical conditions, psychological and behavioral issues.
