I believe the answer is choice D. Hope this helps!!!
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Answer: A) Two atoms share electrons so they can fill their outer shells
Explanation: A covalent bond is a type of bond formed by sharing equal number of electrons between two non-metal atoms so that both of them can attain a stable octet or duplet structure of noble gases.
In covalent bonding, there is no loss or gain of electrons between atoms. For example, the formation of chlorine molecule, chlorine atom has seven electrons in its outermost shell, remaining one electron to attain an octet structure of noble gases. Two chlorine atoms share one pair of electron, each chlorine atom donating one electron to form a pair so that each atom in the chlorine molecule attains an octet structure..
Answer:
D. It is carried out in cells that are involved in sexual reproduction.
Explanation:
Your elbow is a hinge joint (think like a hinge on a door) and your shoulder is a ball and socket joint. Your elbow can only move two directions, but your shoulders can move anyway they want (omni-directional). Hope this helped!