Question: Q: The use of mercury-based dental amalgam has gone under question in recent years because of concerns regarding what? Choices: - the expense - the oxygen - the variability - the toxicity A:
Answer: the toxicity

Question: Q: The part of the ecosystem required by a particular species is endangered when human activity threatens loss of what? Choices: - primary producers - primary speciation - biodiversity - habitat A:
Answer: habitat

Question: Q: Root-like projections anchor adults of what colony-dwelling animals to solid surfaces such as rocks and reefs? Choices: - anemones - corals - molluscs - sponges A:
Answer:
sponges