A student creates a model of a closed ecosystem by filling a glass tank half
full with water, then adding 10 snails and two small aquatic plants. The next
day, all the snails are dead. What is the most likely cause of their death?
A. The amount of nitrogen in the tank became too low.
B. The amount of nitrogen in the tank became too high.
O
C. The amount of oxygen in the tank became too high.
D. The amount of oxygen in the tank became too low.

The amount of oxygen is to low

Explanation:

You also need plants on the surface for the one's who are not under water

the economy of japan in 1945 was completely destroyed. it is a lie that the americans bombed something in japan. they bombed everything and residential areas and factories. the entire industry of japan was eliminated.

during the us government in japan, there was no real development of the industry. japan grew rice, made sake and sold it on the world market, so much that there was a famine in japan.

however, in 1948, the development of some keiretsu began. it began to give growth but not systemic. where the money came from - the united states did not give anything to the keiretsu, not a cent but dzaybattsu in 1943, realizing that the defeat inevitably part of their money through latin america brought to the us by investing in the us economy. for example in the production of aircraft, cars, construction of houses. in 1948 they began to gradually return the money.

in 1950, the korean war began. ships were repaired in japan, japan transported cargoes for this war and people, and provided logistic support. and this earned some money.

in 1952, japan gained independence and the keiretsu began to return money from the united states to japan.

in 1954, the economy began to grow 5% per year. in 1962, due to the actions of the government and the preparation for the olympics, it accelerated to 9%. in 1966 it fell to 6%.

japan reached its prewar level in 1964 at the same time as the olympics.

and then 1968-1989 rapid growth but this is a separate topic.

factors

1. properly allocated resources

2. korean war

3. transistors

4. system change of product structure

but this is interesting

in contrast, the biological controls are self-sustaining, inexpensive and very effective once established. biological control could be used on thousands of golf course acres, improving their biodiversity and quality as wildlife habitat. in the process, the golf industry will be shown to be leaders in an environmental stewardship program of benefit not only to the lands they manage but also to the watersheds in which they exist.