②→ Products __ by famous or popular athletes appeal to a broader consumer base.
endorse
endorsed
endorsing 

③→ Sports are __ promoted to people in order to raise interest and participation in sports.

genuine
generally 
genuinely  

④→  Sports ads are carried out on a variety of __, such as Instagram, Facebook, Twitter, and media advertising.
flat
platform
platforms

⑤→ 名古屋伏見英会話スクール ロケイシャス (LoQuacious) advertises using social media and word of __.
mouth
month
mouse