Why is it difficult to know the impacts of deep sea mining? O It has never been tried successfully, so we don't know exactly how it can be done.
Olt is only done in environmentally sensitive areas, where the organisms are being harmed in many ways already, and it is difficult to know the effects of mining.
We know relatively little about deep sea ecosystems, making it harder to assess the impact of mining.
O Most countries have laws against it, so the impacts have not been tested.

How are tumors cells different from normal cells

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area

How much time has elapsed from the very beginning of "the memior of the conquistador bernal diaz del castillo" to the end? a. castillo's whole life b. a quarter of an hour c. a few weeks d. a decade