Answer:
Arithmetic sequence
for 
Step-by-step explanation:
We are given that a sequence

We have to identify the sequence as arithmetic or geometric and write an explicit formula .







When the difference of consecutive terms is constant then the sequence is an arithmetic.
Hence, the sequence is an arithmetic.

for 
Chlamydia – Chlamydia is a bacterial STD. It can often be treated with just a single round of antibiotics. Gonorrhea – Like chlamydia, gonorrhea is caused by bacteria that can usually be treated with antibiotics, however, there have recently been some cases of gonorrhea that are resistant to antibiotics.
Answer:
8
Step-by-step explanation:
Order the numbers.
5, 5, 5, 8, 8, 9, 9
The total numbers in the list is 7.
7/2 is between 3 to 4
Choose the middle number in ordered list:
5, 5, 5, 8, 8, 9, 9
answers is 8