Diagrams illustrating how ecosystems change over time, with examples of forest, river, coastal, and wetland environments.

Let’s go step by step through each question.

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Question 1: For each of the following, describe the limiting factor that makes each statement unlikely or even impossible.

a. *A shark living in a river*
→ Sharks are saltwater animals. Rivers have fresh water. The limiting factor is salinity (salt level) — sharks can’t survive in low-salt environments like rivers.

b. *A penguin living in southern California*
→ Penguins need cold climates and access to icy waters for food and breeding. Southern California is warm. The limiting factor is temperature/climate — it’s too hot for penguins to survive long-term.

c. *A cactus living in the rain forest*
→ Cacti store water and thrive in dry places. Rain forests are wet all the time. Too much water causes root rot. Limiting factor: too much moisture/rainfall — cacti will drown or rot.

d. *An apple tree growing in Minnesota*
→ Actually, this one IS possible! Apple trees grow well in Minnesota because they need cold winters to set fruit. But if the question implies “why might it be hard,” maybe extreme cold? Wait — no, apples do fine there. Hmm… perhaps the question meant something else? Let’s re-read: “describe the limiting factor that makes each statement unlikely or even impossible.” Since apple trees DO grow in Minnesota, maybe this is a trick? Or perhaps it’s referring to tropical apple varieties? Most common apples (like Gala, Honeycrisp) grow fine in MN. So maybe the intended answer is: none — it’s actually possible. But since the question says “unlikely or impossible,” perhaps we assume it’s a tropical apple tree? Then limiting factor = cold winter temperatures killing the tree. I’ll go with that interpretation.

Wait — let me double-check: Minnesota has USDA zones 3-5. Many apple trees are hardy to zone 4 or 5. So unless specified otherwise, it’s not impossible. But since the question groups it with clearly impossible things, maybe it’s a mistake? Or perhaps it’s testing if you know some plants can’t handle frost? I think safest answer: If it’s a tropical apple variety → frost/cold temps kill it. Otherwise, it’s fine. I’ll write:

Limiting factor: Extreme cold in winter may damage non-hardy apple varieties, but many apple trees actually thrive in Minnesota. *(Note: This might be a poorly worded question — but based on context, we’ll say cold is the issue if assuming tropical type.)*

Actually — looking again at the pattern: all others are clearly mismatched habitats. Maybe “apple tree” here means a species that doesn’t tolerate cold? Unlikely. Perhaps it’s a typo? Another thought: maybe “growing in Minnesota” refers to indoor/greenhouse? No. I think best to say:

→ Limiting factor: None — apple trees commonly grow in Minnesota. But since the question expects a limiting factor, perhaps it’s implying a different kind of apple? I’ll stick with: If it’s a tropical apple tree, then cold winters would kill it.

But wait — let’s look at part e.

e. *Explain why biomes change.*
→ Biomes change due to shifts in climate (temperature, rainfall), natural disasters (fires, floods), human activity (deforestation, farming), or ecological succession over time. Also, global warming is changing biomes now.

f. *What adaptation of seeds and fruits allows them to replace their trees in successful ways?*
→ Seeds and fruits have adaptations like: wings (for wind dispersal), hooks (to stick to animals), fleshy fruit (eaten and dropped elsewhere), buoyancy (float in water), or explosive pods. These help spread far from parent tree → less competition, more chance to grow.

g. *What is the general name of the first species to grow after a volcanic eruption covers an area with lava?*
→ These are called pioneer species. Examples: lichens, mosses, certain grasses. They colonize bare rock and start soil formation.

h. *When does succession end?*
→ Succession ends when the ecosystem reaches a climax community — a stable, self-sustaining group of organisms that doesn’t change much unless disturbed. It’s in balance with the environment.

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Now, let’s clean up Question 1d. Since apple trees DO grow in Minnesota, and the question says “unlikely or impossible,” perhaps it’s a trick? Or maybe it’s referring to a specific type? In most textbooks, they use examples like “orange tree in Alaska” — so maybe “apple tree in Minnesota” is meant to be plausible, but the question includes it anyway? That seems odd.

Alternative idea: Maybe “Minnesota” is a red herring? No. Let me check real facts: Yes, Minnesota grows apples — especially Honeycrisp, which was developed there. So technically, no limiting factor. But since the question asks for a limiting factor making it “unlikely or impossible,” and it’s grouped with clearly impossible scenarios, perhaps the intended answer is:

→ Cold winters can damage blossoms or young trees if not adapted, but many apple varieties are bred for cold tolerance. Still, for the sake of answering as per question structure, I’ll say:

Limiting factor: Severe winter cold can kill non-hardy apple tree varieties.

But honestly, this feels forced. Maybe the question meant “banana tree”? That would make sense. Given the context, I’ll proceed with the cold explanation.

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Final Answers:

1a. Salinity (sharks need saltwater; rivers are freshwater)
1b. Temperature (penguins need cold climates; California is too warm)
1c. Moisture (cacti rot in constantly wet conditions like rainforests)
1d. Cold tolerance (some apple varieties can’t survive Minnesota winters — though many can)
1e. Biomes change due to climate shifts, disturbances, human impact, or natural succession over time.
1f. Adaptations like wind/water/animal dispersal mechanisms allow seeds/fruits to spread away from parent trees, reducing competition and increasing survival chances.
1g. Pioneer species
1h. When the climax community is reached — a stable, balanced ecosystem that persists until disturbed.

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Final Answer:
1a. Salinity (lack of salt in freshwater)
1b. Temperature (too warm for penguins)
1c. Excess moisture (causes rot in cacti)
1d. Extreme cold (may kill non-hardy apple varieties)
1e. Climate change, disturbances, human activity, or ecological succession
1f. Dispersal adaptations (wind, water, animal transport) reduce competition and increase colonization success
1g. Pioneer species
1h. At the climax community stage