20.4 21.3 are the correct answers
Question 1: The correct answer should be the one that shows the producer first, (->) followed by the herbivore, (->) with the carnivore last.
Producers are organisms that harvest their own 'food' using things like the sunlight and water. Examples of producers are grass and other vegetation.
The herbivore, or an organism that consumes only vegetation and/or algae, consumes the producer.
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The carnivore consumes meat, or other animals such as the herbivore. It's the last.
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Therefore the answer is
B.
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Question 2: I'm pretty sure that succession as well as regrowth after volcanic eruption (Just look at Mount St. Helens. After 30-35 years after the eruption, nature is
still recovering) happens over time/slowly. I would say global warming [C](?) would be the answer.
Answer is A
Firstly axon must reach the threshold level and then depolarisation occurs. Depolarisation phrase means sodium enters and potassium leaves the axon . Choice C can't be because main idea is the entering of sodium ions.
Answer:
The nervous system releases neurotransmitters at synapses at specific target cells & The endocrine system reacts more slowly to stimuli, often taking seconds to days.
Explanation:
The nervous system is very specific with where the neurotransmitters go so they will affect target cells. The endocrine system is slower than the nervous system because the hormones travel through the blood so it takes much longer to reach the designated area.