Answer:
The correct answer will be- Crop rotation
Explanation:
When the growth of a type of crop which uses soil nutrients in abundance and then growing another crop in the same filed led to the decrease in the production of the next crop.
Thus farmers adapted to avoid such farming practices and developed a new practice which allowed the land to become fertile again so that the growth of next crop will not be affected.
The practice involved the planting of a crop on a piece of land then leaving the soil ploughed and unsown for a longer period of time and growing corp on another piece of land allowing the time to restore the nutrient content. This practice is known as "crop rotation".
Thus, crop rotation is the correct answer.
<span> For a start, when you have a question that needs answering in science, you formulate a null hypothesis. That is a negative statement which you then set out to prove or disprove. This is just a convention. So if your initial question is for example, "Does sugar dissolve in water?"
Your null hypothesis will be "Sugar does not dissolve in water."
You then set up your experiment and get some data.
Now if your data doesn't support your null hypothesis then you reject it and make the statement ,"Sugar does dissolve in water." As you can see from this simple example, a non-result is still a result so the idea of formulating new tests as mentioned by another answerer isn't necessary and in some ways is the incorrect thing to do. In science, hypotheses are often not supported by data and i would argue that this is the case a lot of the time. A non-result is still a result and you will have plenty to write about whichever way it goes. </span>
Answer:
Pregnancy, which is characteristically associated with changes in hormone levels in the body is a process tightly regulated by the hormon Human Chorionic Gonadotropin
Explanation:
The so-called pregnancy hormone is the Human Chorionic Gonadotropin (HCG). It only occurs during the gestation period and is responsible for regulating the entire process. Segregated by the placenta, it can be found in urine and blood.
The presence of the hormone in the urine allows to confirm the pregnancy with the test. As in pregnancy, the placenta begins to form, the cells that make it up begin to stimulate the production of HCG, which causes the hormone levels to increase very rapidly in the first trimester of pregnancy
Elephants in the savanna regions of Africa dig holes in dried up river beds to reach water lying just below the surface. These holes provide drinking water for other animals as well. So, without the elephants, many animals might otherwise die from lack of water during the dry season. The location in which the elephants live is an example of a/n habitat and the role they play in creating water holes is an example of a niche.
