Answer would be C, Physical Change, it's similar to crumpling up a piece of paper
1. An ionic bond is an attraction between oppositely charged ions. A covalent bond is sharing of electrons between atoms.
2. A bond between two atoms
3. covalent bond
4. They have different properties because the arrangement of atoms is different.
5. Mutual attraction between the nuclei and electrons in two different atoms
Well, you could get the mass as

ad then

, where

is the sea level weight,

the sea level accel.,

the accel. above while

the weight above.
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Answer: Cell components encompass phagocytic cells, epithelial and endothelial cells, natural killer cells, innate lymphoid cells, and platelets.
Explanation: Although it is ancient, the innate immune system is highly complex and consists of barriers to infection (epithelia of skin, gastrointestinal, respiratory, genitourinary tracts), antimicrobial peptides and proteins, humoral components (i.e. complement and opsonins) and cellular components (i.e. neutrophils, monocytes).