Broadly speaking, a pathogen is a microbe that causes disease. So the most accurate answer here would be the last answer choice.
Answer:
As water freezes, a crystalline structure preserved by hydrogen bonding is formed by water molecules. Less dense than liquid water is solid water, or ice. Ice is less dense than water since molecules are pulled farther apart by the direction of hydrogen bonds, which decreases density.
Explanation:
For the atom to be neutral, it must have the same number of electrons and protons. The aromic number indicates the number of protons. Since Carbon has 6 protons, it would have to have 6 electrons for it to be neutral
The given question is incomplete. The complete question is:
Which is true of Elements on a periodic table in the same group (family)?
A; Elements in the same family have similar chemical properties because they have the same number of electron shells.
B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.
C; Elements in the same family have few similar properties as they have different numbers of electron shells.
D; Elements in the same family are always the same type of Elements and have the same number of protons.
Answer: B; Elements in the same family have similar chemical properties because they have the same number of valence electrons.
Explanation:
Elements are distributed in groups and periods in a periodic table.
Elements that belong to same groups will show similar chemical properties because they have same number of valence electrons.
The chemical reactivity of elements is governed by the valence electrons present in the element.
Example: Flourine, chlorine and bromine are elements which belong to Group 17. They have 9, 17 and 35 electrons respectively and contain 7 valence electrons each and need one electron to complete their octet.
It will be:
b. Alkyne* series
* You have done a spelling mistake here. It will be "Alkene" not "Alkyne".