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irina [24]
2 years ago
7

Which of the following events occurred during the first trimester?

Biology
1 answer:
klasskru [66]2 years ago
5 0
I believe that the answer to your question would be A. Heart Begins.
You might be interested in
4. Which of the following elements does not want to have eight valence electrons? a. magnesium c. hydrogen b. oxygen d. nitrogen
Cloud [144]

Answer:

Hydrogen.

Explanation:

Hydrogen is the simplest chemical element that exists. The symbol for the chemical element Hydrogen is "H" and it is a colourless, tasteless, odorless, and highly flammable gas.

Hydrogen is a chemical element found in group (1) of the periodic table and as such it has one (1) electrons in its outermost shell. Therefore, Hydrogen has an atomic number of one (1) and a single valence electrons because it has only one proton and one electron in its nucleus.

Based on the octet rule which states that atoms of chemical elements gain, lose or share electrons so as to have eight (8) electrons in their valence shell. Therefore, atoms of chemical elements bond in order to attain the electronic configuration of a noble gas i.e a full valence shell which comprises of eight (8) electrons.

However, the chemical element "Hydrogen" is an exception to the octet rule because it is only able to hold a maximum of two (2) valence electrons in its outermost shell to become full.

<em>Hence, Hydrogen is an element which does not want to have eight valence electrons. </em>

7 0
2 years ago
Almost all the South American and Central American
Vedmedyk [2.9K]

Answer:

O founder's effect

Explanation:

A founder effect can be defined as the loss of genetic variation when a new population is established from a few individuals. This process is known to increase the frequency of particular gene variants (alleles) at different <em>loci</em> when they are selectively neutral (or nearly neutral), and thereby such genes are fixed by genetic drift (i.e., through the random sampling of founder individuals). Interestingly, it has been discovered that the majority of South American and Central American Indians are nearly exclusively in the O blood group, which has been further associated with random genetic drift and a founder effect.

8 0
3 years ago
An example of an everyday device that uses semiconductors would be a drinking glass.
sergey [27]
False let me know if you would like me to explain.
8 0
2 years ago
An acidic solution of pH 5 has<br> TIMES as many hydrogen ions (H+) as does a solution of pH 6.
Artyom0805 [142]

The difference in concentration of hydrogen Ions between pH5 and pH6 is - x 10.

The pH scale is a scale or measure to find the strength of acidity or the basic nature of a solution or substance. pH 1 is acidic and pH 14 is the most basic on the scale.

  • The concentration of hydrogen ions is inversely related to its pH
  • More hydrogen ions present, the lower the pH
  • The fewer hydrogen ions, the higher the pH We know,

pH = -log(H+) then,    

=> 5 = -log (H+)

=> H+ = 10^{-5} (for pH = 5)    

=> pH = -log(H+)  

=> 6 = -log (H+)  

=> H+ = 10^{-6}  (for pH = 6)  

Thus, The substance with the lower pH (5) has 10 times as many hydrogen ions per volume of water.  

Learn more about the pH scale:

brainly.com/question/1596421

7 0
2 years ago
Which is a positive effect of the technological advance of going from a<br> compass to a GPS?
Hunter-Best [27]

Answer:

The positive effect of the application of a GPS over a compass is that one can get success in getting to his or her desired location. A GPS can inform about the exact location, and when it is combined with a map, it makes the person reach straight to where he or she desires to go

8 0
2 years ago
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