Question

env.6 - high levels of biodiversity tend to - *

• have little or no effect on ecosystems
• decrease an ecosystems resistance
• increase the stability of an ecosystem
• make an ecosystem less resilient

env.7 - a renewable resource is harvested sustainably if - *

• soil erosion is prevented
• replacing trees costs less than harvesting trees
• the amount of replacement is equal to the amount harvested
• the amount of replacement is less than the amount harvested

env.7 - all fossil fuels are considered to be nonrenewable because - *

• humans are using them too fast
• they are organic
• they cause global warming
• they take millions of years to form

Explanation:

• For the first question, high - biodiversity ecosystems have more species and complex interactions, which enhance stability.
• For the second question, sustainable harvesting of a renewable resource means the rate of replacement equals the rate of harvesting to maintain the resource over time.
• For the third question, fossil fuels are non - renewable because their formation process takes millions of years, much longer than the time scale of human consumption.

Answer:

• ENV.6: increase the stability of an ecosystem
• ENV.7: the amount of replacement is equal to the amount harvested
• ENV.7: they take millions of years to form