Answer:
The thyroid gland increase in size.
Explanation:
Iodine plays an important role in the generation of thyroid hormones and is mainly found in the soil in coastal areas and in seawater. In the developing nations, the individuals who live at high elevations or inland are generally deficient in iodine and can develop a condition known as goiters.
In the condition, the thyroid gland increases in size in an attempt to get more iodine. However, in the countries where iodine is added routinely to foods and table salt, the lack of dietary iodine is not the typical reason of goiters.
Primary succession begins on rock formations, such as volcanoes or mountains, or in a place with no organisms or soil.
Answer:
An experiment imposes treatment on the subjects, but an observational study does not
Explanation:
Observational studies are research studies in which an effect, process behaviour etc. are observed, without any change. For example, observation of the possible effect of a treatment on subjects.
On the other hand, experimental studies are studies in which the treatment is included. Experimental studies are randomized, meaning that subjects that are in experiment are randomly put to a treated group or a control group.
