An atom will usually form either an ionic bond or covalent bond with another atom but not both.
Ionic bonds are the kind of bonds that result when one atom transfers or gives up electrons and another atom receives them and adds them to its own energy shells.
An example is sodium metal and chlorine gas. Sodium gives up two of its electrons and Chlorine receives them and the two elements form an ionic bond to create sodium chloride, a new compound.
Covalent bonds are the kind of bonds formed when two atoms decide to share electrons. No atom gives up any electrons and neither does the other atom receive any. An example is water. An oxygen atom shares two of its electrons with two hydrogen atoms to form a molecule of water (H2O).
I think the correct answer would be strong gravity. The factor that allows the earth to hold onto water would be the strong gravitational pull of the earth. In fact, it is what holds everything onto earth not only water. Hope this answers the question.
Blood
Blood is the transport fluid circulating in the body and is responsible for the transport of substances from one point to another. Blood is composed of red blood cells, white blood cells, platelets and plasma. All of these components work together and transport substances such as oxygen, glucose and amino acids to the cells and remove waste substances such as carbon dioxide and urea away from the cells.
Fred must have suffered muscle atrophy.
Explanation:
Since Fred broke his leg and a cast was put around his leg,his orthopedic must have suggested restricted movement of his leg as a part of treatment.. Due to this immobilization the muscle mass of his leg may have got wasted and his leg became weak. Being too weak the leg may not have supported the body weight and Fred fell.