Answer:
A. a developing nation
Explanation:
Age pyramids are the age structure diagrams that represent the number and proportion of people at each age in a population. The base of the age pyramids represents the population in pre-reproductive age which is from 0 to 10 years. The overall shape of an age pyramid indicates if the population is increasing, stationary, or shrinking.
The age structure diagram for a developing nation has a broad base that tapers quickly towards the top. This means that a larger percentage of the population is in the pre-reproductive age group and reproductive age group with a smaller percentage of the population in the post-reproductive age. These countries have a great chance of future population growth.
Answer: Positive feedback loop
Explanation:
Even before the food reaches the stomach (before ingesting it), the glands of the stomach mucosa begin to release its gastric secretion. The main characteristic of this secretion is acidity, as measured by pH (one of the physiological variables).
This acidity is a result of the presence of hydrochloric acid, which is part of the secretion composition. In addition to it, water, pepsinogen (which will give rise to the enzyme pepsin) and the intrinsic factor. The acid has a function of the protection of the entire system by eliminating microorganisms. It is also responsible for the activation of pepsin (which only occurs with acid pH), the enzyme that digests proteins containing the amino acids leucine or phenylalanine or tryptophan or tyrosine.
The concept of Positive feedback loop states that the body tries to increase the value of a variable (acidity, in the case of pepsinogen) when it is below its optimal value (called a point adjustment) and decreases this value when it is above optimal.
