1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Verizon [17]
3 years ago
10

Blood calcium is regulated by a hormonal control system. normal blood calcium levels are 8.5 to 11 mg/dl. when calcium levels ar

e too high, the thyroid detects this and releases calcitonin. calcitonin stimulates the kidneys to release more calcium and it causes bones to absorb more calcium and build more matrix. identify the elements of this control system by matching the items below. some answers will not be used and some may be used more than once.
Biology
1 answer:
sattari [20]3 years ago
4 0
FEEDBACK MECHANISM is a regulatory mechanism in which presence of certain level of substance promotes or inhibits its further formation.
The regulation of secretion of Thyrocalcitonin from thyroid gland is an example of such feedback control mechanism. It occurs in two ways:

a) When calcium levels are too high, the thyroid detects this and releases calcitonin. calcitonin stimulates the kidneys to release more calcium and it causes bones to absorb more calcium and build more matrix. This is called Negative Feedback Control.

b) In response to a decrease in calcium levels, parathyroid hormone is released, which causes the release of calcium from bone and retention of calcium in the body, and the calcium level rises back to normal. This is called Positive Feedback Control.
You might be interested in
celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution b
maxonik [38]

Celery stalks that are immersed in fresh water for several hours become stiff and hard. :333333

3 0
3 years ago
Describe the concept of natural selection, using the Galapagos finches as an example. Imagine you were trying to explain the con
Trava [24]

Answer and Explanation:

Natural selection is the result of the phenotype-environment interaction which determines gene destiny in space and time, selecting beneficial alleles and increasing their frequency in the population. It is a consequence of the individual differential capability to reproduce and leave offspring. There must be also a genetic base called heritability. Natural selection involves interactions between individuals, the physical environment, and the biological environment.  

Natural selection results in adaptation, an increase of the aptitude phenotype.  In many cases, adaptations, resulting from natural selection, can be correlated to environmental factors or selective pressures applied by other organisms.

The selective agent is the environmental characteristic that determines the differential survival of the phenotypic classes.  

Some intraspecific phenotype variations follow a geographical distribution and can be correlated to changes in environmental conditions, such as temperature or humidity.  

Adaptive evolution refers to changes in the organism that lead to the evolution of the species and that are adaptive to certain conditions of the environment. Birds adapt to diverse ecological niches showing specialized beak forms to improve functions such as feeding, mating, defending, competing, and etcetera. These factors play an important role in beak shaping. Natural selection produces adaptive evolution.

During 1977 Daphne Major island went through an important drought, and many plant species produced few or no seeds during and after the event. The medium ground finch population, which is seed-feeder species, was hardly affected by this phenomenon. As seeds´ production dropped and the sizes of the extisting seeds were considerably smaller, the finch population declined drastically from about 1400 individuals to a few hundred in a period of two years, approximately. The fact is that the island weather controls plant species development, and thus, seeds availability as food for the birds. Years later after the drought, the finches population managed to recover but showing differences in the size of their beaks. Before the drought finches had a stubby beak and many years after recovering the average size of the beaks was larger than the beak size of the original population.  This difference in phenotype was due to the fact that during the drought, small seeds were very scarce, but large seeds with thick husks were still available. Small birds with small beaks starved because they were not able to open the husk and eat the interior of the seed. But those birds with bigger and stronger beaks were able to do so, and hence, managed to survive. The bird population adapted to the new environmental conditions and resource availability. Natural selection acted on the beak size, changing it.  

There are different kinds of natural selection, but in the present example, directional selection is operating.  

<u>Directional selection</u> increases the proportion of individuals with an extreme phenotypic trait, in this case, large beaks. This selection presents more frequently in those cases in which interactions between living organisms and the environment modify in the same direction.

Furthermore, beak size is not only related to feeding strategies, but also to reproduction. Female finches only mate with males that have the same beak size.

4 0
3 years ago
What is the role of the seminal vesciles and the prostate gland​
geniusboy [140]

Answer:

The seminal vesicle and the prostate glands add their secretions so that the sperm are in a fluid that makes their transport easier, and this fluid also provides nutrition.

Explanation:

3 0
2 years ago
A student is investigating the question “Which increases a person’s breathing rate more after three minutes, lifting five-pound
LenaWriter [7]
The breathing rate is the dependent variable because it can be affected by varying weights.

P.S the answer was on quizlet
5 0
3 years ago
A 2-kg bowling ball sits on top of a building that is 40 meters tall.
Alchen [17]
Okay, so this is physics. What is the meaning of KE? It's Kinetic Energy. What is the meaning of GPE? It's Gravitational Potential Energy. So how do you calculate either, and what are their significances? Kinetic -> motion, Gravitational potential energy -> energy that can be used to do work due to gravity. So is the bowling ball moving, or is it someplace it can fall from, or both?

Kinetic energy is calculated as 1/2 * mv^2, where m is the mass of the object, and v is the velocity. Potential energy for conservative forces is the product of the force and the distance over which it can do work. Thus in the case of GPE, it is the weight multiplied by the height, as gravity is a conservative force. What is the weight? It's not equal to the mass.

Hopefully these hints will get you thinking.
8 0
3 years ago
Other questions:
  • 01.04 LC)Water is often called the "universal solvent" because many substances can be dissolved in water. What property of water
    11·2 answers
  • The method by which new genes can be acquired by successive generations:
    11·2 answers
  • What phase of mitosis involves the chromatids aligning in the center of the cell?
    12·2 answers
  • During an experiment, readings for blood pressure in a person’s body were found to be constant. However, when measured by a diff
    5·1 answer
  • When did Madagascar break away from the south america african part of Gondwanaland
    5·1 answer
  • A gene that overpowers a weaker gene<br> A.genotype<br> B.phenotype<br> C.dominant<br> D.recessive
    5·2 answers
  • Each step or level of the food chain forms a__________
    11·2 answers
  • Please help asap
    13·1 answer
  • We use genetically modifed animals for protein tracking as well as novelty pets.
    15·1 answer
  • Match the plant part with the food.
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!