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.
I'm not sure what you're asking, but if you're looking for a word to describe this change its "mutation"
Answer:
It would have to be passive immunity
Explanation:
Because active immunity develops after being exposed to the pathogen and its not acquired either because its similar to active and it isn't inborn because that comes from your parents
Parietal cells produce gastric acid (hydrochloric acid) in response to histamine (via H2 receptors), acetylcholine (M3 receptors) and gastrin (gastrin receptors). Parietal cells contain an extensive secretory network (called canaliculi) from which the HCl is secreted by active transport into the stomach.
D. Carnivores that eat other animals
A biotic factor is a living organism that shapes its environment.