The death rates in the United States decreased more than 40 percent from 1930 to 2015. Which factor could have contributed to this decrease? OA
increased food insecurity
OB
better medical facilities and treatments
C.
decreased farmland
OD
refusal of vaccines
E
illiteracy

The correct answer is - B. better medical facilities and treatments.

In the past century, the life expectancy in the United States have increased significantly, in fact it is almost doubled. The death rates have decreased for around 40% and the biggest reason for this trend are the advancements in the medical field. The medical facilities and treatments have improved significantly. The technological advancements contributed to the medical field a lot, made it much more efficient, and because of that the prevention of diseases, curing, and the saving of lives have skyrocketed, resulting in much better, healthier,and longer life of the population

i hope this will help u

mark it as brainliest

and rate it

Explanation:

answer; a muscle cell, another neuron and a of the above

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.