Extinction and speciation rates.
Who doesn't drink enough water so the salt of the food will be stored in human body causing many health problems
Answer:
4.6 to 4 Billion Years Ago
Explanation:
According to the researchs and studies, the earth formed about 4.54 billion years ago and the oldest known living organism date to around 3-3.5 billion years ago which are the first bacteria that formed in the water.
I hope this answer helps.
Answer: C): the number of unpaired electrons.
Explanation: A covalent bond is a type of chemical bond formed by sharing equal number of electrons between two non-metal atoms so that both can attain the a stable octet or duplet structure of noble gases. The electrons shared by two non-metal atoms are the unpaired electrons. For example, in the formation of a chlorine molecule, a chlorine atom has seven valence electrons and electrons usually occur in pairs. Having seven valence electrons means that a chlorine atom has three pairs of electron and one unpaired electron in its outermost shell. The two chlorine atoms will combine together each donating its unpaired electron to be shared, thus leading the two atoms to attain stable octet structure of Argon.
