B as the broken down molecules can be made into useful substances for the body
A secondary source is anything written after the fact
Answer:
The correct answer is option A) "cause iron in ocean water and terrestrial rocks to rust (oxidize)".
Explanation:
During ancient times, the reproduction success of plants and cyanobacterias led to the accumulation of oxygen gas in the atmosphere. One early consequence of this accumulation was the oxidation of the iron in ocean water and terrestrial rocks. This phenomenon is the cause of banded iron formations, which formed in seawater and sank to the ocean bed.
The given is incomplete as the options are missing. The correct options for the given question are as follows-
(A) cultivation of agricultural land inhibits the decomposition of organic matter
(B) nitrogen-fixing bacteria are not as plentiful in agricultural soils because of the use of pesticides
(C) land that is available for agriculture tends to be nutrient-poor
(D) the nutrients that become the biomass of plants are not cycled back to the soil on lands where they are harvested
Answer:
Option (D)
Explanation:
In order to carry out agricultural practices, the soil must be rich in essential nutrients for the growth of crops. The soil fertility is a key role in the production of crops.
This agricultural land often requires a large amount of these nutrients and minerals because some of the nutrient minerals are converted into plant biomass which is then used up to produce energy in other sectors. So, the nutrients that were present in the soil are taken away and not transferred back into the soil. This means that the nutrient cycle gets affected. Due to this reason, there requires a constant supply of nutrients into the agricultural fields.
Thus, the correct answer is option (D).
