Question

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select two differences between primary and secondary
ecological succession

primary succession is the first stage and secondary is the second
stage

primary builds plant community; secondary builds animal
community.

primary begins with soil; secondary begins without soil

primary begins without soil; secondary begins with soil

pioneer species in primary succession are lichen and moss, while
grass is the pioneer species in secondary succession

Explanation:

1. Analyze each option:

• Option 1: Primary and secondary succession are not simply "first" and "second" stages in a linear sense of the same process. Primary succession starts on bare, lifeless substrates (like rock), secondary on disturbed areas with soil, so this is incorrect.
• Option 2: Both primary and secondary succession involve building both plant and animal communities as succession progresses, so this is incorrect.
• Option 3: This is the opposite of the truth. Primary succession starts without soil (e.g., on rock), secondary with soil (e.g., after a fire in a forest), so incorrect.
• Option 4: Primary succession begins on substrates without soil (e.g., newly formed rock from a volcano), and secondary succession begins in areas where soil already exists (e.g., after a forest fire or human disturbance that removes vegetation but leaves soil), so this is correct.
• Option 5: Pioneer species in primary succession are often lichens and mosses (they help break down rock to form soil), and in secondary succession, since soil is present, pioneer species can be faster - growing plants like grasses (which can colonize disturbed soil quickly), so this is correct.

Answer:

D. Primary begins WITHOUT soil; Secondary begins WITH soil
E. Pioneer species in primary succession are lichen and moss, while grass is the pioneer species in secondary succession