Answer:
○Two electrons in the outer shell and a full outer electron s shell
○Low electron affinities
○Low electronegativities
○Relatively low densities
○Relatively low melting points and boiling points, as far as metals are concerned
○Typically malleable and ductile. Relatively soft and strong.
The elements readily form divalent cations (such as Mg2+and Ca2+).
The alkaline earth metals are very reactive, although less so than the alkali metals. Because of their high reactivity, the alkaline earths are not found free in nature. However, all of these elements do occur naturally. They are common in a wide variety of compounds and minerals.
These elements are shiny and silver-white as pure metals, although they usually appear dull because they react with air to form surface oxide layers.
All the alkaline earths, except for beryllium, form corrosive alkaline hydroxides.
All of the alkaline earths react with halogens to form halides. The halides are ionic crystals, except for beryllium chloride, which is a covalent compound.
Answer:
The correct answer is a. divergent evolution.
Explanation:
Divergent evolution leads to the evolution of different species which becomes dissimilar to each other due to evolutionary change. The change may occur due to change in their environment and niche. Species originated from divergent evolution have the same common ancestor.
Divergent evolution results in homologous structures for example animals like mammals, birds, reptiles, and amphibians are evolved from a common ancestor and have homologous structure as 5 digits pentadactyle limbs.
So humans also have 5 digits pentadactyle limbs and elephants also have 5 digits pentadactyle limbs which is an example of divergent evolution.
Therefore, the correct answer is a. divergent evolution
.
Nervous muscle action pressure
Answer:
C. Aldosterone increases sodium reabsorption by increasing the number of Na+-K+ ATPase pumps in the luminal membrane of the proximal tubule.
Explanation:
- Aldosterone hormone is produced by the adrenal gland and mainly carries out its functions in the kidney.Through the aldosterone hormone the body is able to retain more water for the kidney is able to hold more sodium.
- When the plasma sodium levels decrease and the plasma potassium levels increase the production of aldosterone hormone is stimulated for sodium is needed in the .body to maintain the high water levels in the body.
