I think it is DATABASE correct me if I'm wrong
Radiation is when heat travels through space.
Answer:
The different variable in C is 21213316700.
Explanation:
Given value:
Total value = letters + underscore value
Total value = 52 + 1
Total value =53
choice for first character = 53 letters +10 digits
first character = 63
choice for remaining characters
So,
Variable number With one 1 character = 53
Variable number With 2 character = 53 × 63
Variable number With 3 character = 53 × 63²
Variable number With 4 character = 53 × 63³
.
.
.
Variable number With 7 character = 
Total difference variable = 53 + 53 × 63+ 53 × 63²+ 53 × 63³+....+ 
Total difference variable = 53(1 + 63 + 63²+ 63³+ .... +
)
Formula:

Total difference variable

Answer:
These all are constructors.
<u>CONS</u>
(CONS A B)
makes a pair like this: (A . B)
In other words, A is the CAR of the pair; B is the CDR of the pair.
For example:
(CONS 4 5) ==> (4 . 5)
(CONS 4 '(5 6)) ==> (4 5 6)
[The pair (4 . (5 6)) is the same thing as (4 5 6)].
<u>APPEND </u>
(APPEND A B)
makes a new list by replacing the final nil in A with the list B. A and
B must be proper lists.
For example:
(APPEND '(4) '(5 6)) ==> (4 5 6)
This takes any amount of number and put in this order
<u>LIST </u>
In this ,it will return a list whose elements are value of arguments in the order as it appeared in the LIST.It can take any amount of parameters
For example,
(LIST 4) ==> (4)
(LIST 4 5) ==> (4 5)
(LIST 4 5 '(6 7)) ==> (4 5 (6 7))
(LIST (+ 5 6)(* 5 6)) ==> (8 9)
A.
Not B because a guitar has no moving parts.
Not C because guitars receive all the power they need from a cord.
And not D because a guitar is not a car and doesn't need to move!