Answer 1

An enum contains labels for constant values (not changing) it's similar to:
#define VALUE_A 0
#define VALUE_B 1
#define VALUE_C 2

Enums most often contain a group of related constants where the value of its first member is 0 and increases by one for each constant in the enum (by default). You can assign a value to an enum member and the value of the next member will be one higher.

An array is a block of contiguous memory that can be of any variable type: char, int, float, etc and its values can be changed throughout your program. If uninitialized the array will contain garbage values, unlike the enum.

Both are often used together. Say you have 3 strings which specify colors red, blue and green in hexadecimal and an enum that contain the name of each color:

enum color_names {
RED,
GREEN,
BLUE
};

const char *colors[3] = { "#ff0000", "#00ff00", "#0000ff" };

If you want to get the hex number for the color green, instead of doing:
printf("Green = %s\n", colors[1]);
you can do:
printf("Green = %s\n", colors[GREEN]);

Which is much more clear and easier to understand.