All artificial reefs serve a main purpose of improving the abundance and diversity
of life in the ocean.

the platforms age, the populations of fish and other marine organisms that live near the structure increase. ... Artificial reefs provide shelter, food and other necessary elements for biodiversity and a productive ocean. This in turn creates a rich diversity of marine life, attracting divers and anglers.

Explanation:

the hollywood film industry of 1950 was threatened on several different fronts. television broadcasting was rapidly becoming the dominant entertainment medium in the united states. the paramount anti-trust consent decree requiring separate ownership for production companies and theater chains had gone into effect on 1 january 1950. large numbers of young men and women were marrying, having children, and moving to the suburbs, which affected the viability of downtown first-run movie theaters. foreign revenues were endangered by protectionist tactics including quota systems, high taxes, and blocked funds. finally, the morality and patriotism of hollywood films and filmmakers were under attack from government, religious, and citizens' groups.

explanation:

2. a land bridge connected asia and north america thousands of years ago.

4. crossing the land bridge would have been simple for the first migrants.

5. people might have crossed a land bridge while hunting animals.