By the year 2050, the world’s population is projected to be a. 3 billion b. 5 billion c. 7 billion d. 9 billion  

The correct answer is option D

The world's population by 2050 will be 9 billion. This is due to the the advancement in technology, industrialization, better treatment of diseases , et cetera.

The advancement in technology had made the life better and comfortable and the death rate of the people has reduced as it was in earlier days due to certain problems.

The industrialization has also given better life to the individuals.

Earlier people died because of different kinds of disease whose treatment was not available but now to advancement in technology and medication people tend to survive more.

answer; i believe that the correct answer is ; males are hemizygous for the x chromosome;

answer; polycythemia is the correct answer;