Which option correctly describes the nature of nerve signals?

nerve signals are electrical. they move along nerve cells from the point of contact to the spinal cord and then to the heart.
nerve signals are electrical. they move along nerve cells from the point of contact to the spinal cord and then to the brain.
nerve signals are mechanical. they move along nerve cells from the point of contact to the spinal cord and then to the heart.
nerve signals are mechanical. they move along nerve cells from the point of contact to the spinal cord and then to the brain.

After which event could you say that evolution has occurred? question 1 options: an allele frequency changes in a population. a white-eyed fly is born into a population of brown-eyed flies. a new predator comes into an environment. an animal gets fat.

Getting out of bed is the first goal i tackle each day. 2several small goals are achieved by me as the day progresses. 3when i am riding the bus home or walking the dog, i think about the bigger goals i have for my life. which statement correctly describes the verb tense, aspect, and voice in this paragraph? a.sentences 1 and 2 contain present progressive verbs. sentence 3 contains both present progressive and simple present verbs. sentence 2 uses passive voice. b.sentences 1 and 2 contain simple present verbs. sentence 3 contains present progressive verbs. all three sentences use active voice. c.sentences 1 and 2 contain present progressive verbs. sentence 3 contains simple present verbs. all three sentences use active voice. d.sentences 1 and 2 contain simple present verbs. sentence 3 contains both present progressive and simple present verbs. sentence 2 uses passive voice.

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms