Answer:d.
Explanation:hope you guys got it that’s what I got and it was right
Three scientists are credited with the development of cell theory. Matthias Schleiden observed that all plants were made of cells; Theodor Schwann observed that all animals were also made of cells; and Rudolf Virchow observed that cells only come from other cells.
Answer: Pigeon and duck.
Explanation:
From that side of the tree, you can see that the pigeon and the duck are closest together in the tree than the other organisms in the other options.
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>
