A unit cell of NaCl contains a total of 4 atoms. This is because NaCl has a face-centered cubic crystal structure, with one Na+ ion at each of the eight corners of the cube and one Cl- ion at the center of each face of the cube. Therefore, each unit cell contains 1 Na+ ion and 1 Cl- ion, resulting in a total of 4 atoms. **

The cell is referred to as the smallest viable unit of plant or animal life because it is the basic structural and functional unit of all living organisms. Cells are capable of carrying out all the processes necessary for life, such as metabolism, growth, and reproduction. They are also able to respond to their environment and maintain homeostasis. Without cells, plants and animals would not be able to survive and carry out the essential functions needed for life. Therefore, the cell is considered the smallest viable unit of plant or animal life. **

The special unit referred to in the text is the Special Weapons and Tactics (SWAT) team. SWAT teams are specialized law enforcement units trained to handle high-risk situations such as hostage rescues, counter-terrorism operations, and armed confrontations. These units are equipped with specialized weapons, tactics, and training to respond to dangerous and volatile situations that regular law enforcement may not be equipped to handle. **

Protective gear is typically the most expensive out of the three options. This includes items such as helmets, pads, and other safety equipment for activities like motorcycling, snowboarding, or cycling. While cell phones and driver's licenses also come with costs, the initial and ongoing expenses for quality protective gear can be higher due to the need for specialized materials and technology to ensure safety. **

The daughter cell may or may not have the same cell type as the mother cell. During cell division, if the daughter cell undergoes differentiation, it may develop into a different cell type than the mother cell. However, if the daughter cell undergoes mitosis, it will be an exact copy of the mother cell and will have the same cell type. Therefore, whether the daughter cell has the same cell type as the mother cell depends on the specific context of the cell division process. **

Unit A is the unit that measures volume, as indicated by the cubic shape in the diagram. This unit is likely either in cubic meters (m^3) or cubic centimeters (cm^3), depending on the scale of the diagram. Volume is a measure of the amount of space occupied by an object or substance. **

A unit vector is a vector with a magnitude of 1. To determine the unit vector of a given vector, you can divide each component of the vector by its magnitude. This will result in a new vector with the same direction as the original vector, but with a magnitude of 1. Unit vectors are often denoted with a hat symbol, such as "û". **

A unit of measurement is a specific quantity used as a standard for measurement. It provides a reference point for comparing and quantifying physical quantities such as length, mass, time, and temperature. Units of measurement are essential for ensuring consistency and accuracy in scientific, industrial, and everyday measurements. They allow for clear communication and understanding of the magnitude of a particular quantity. **