The quiz is interesting and informative, question 25 is just inaccurate, because "a packet of information that travels between a browser and the web server" can be many many more things than just a cookie (especially because what is referred to as a "cookie" is usually what's stored on the client's server), for example using Telegram Web to send a friend a text is also "a packet of information that travels between a browser and the web server", yet this isn't a cookie. By this definition, the other answers could be true too - Adware could certainly be sent to the browser as a packet of information.
Unfortunately, this test will not be able to receive a prize:
Not an original test. Questions, answers, explanations were copied from different websites. E.g. #q11 <= https://studysite.org/Discuss/Question/the_most_common_format_for_a_home_video_recorder_is_vhs_vhs_stands_for-29219014.htm
#q13 <= https://curioustab.com/discuss/45099/who-created-pretty-good-privacy-(pgp)/
#q14 <= https://curioustab.com/discuss-question/45136
By this definition, the other answers could be true too - Adware could certainly be sent to the browser as a packet of information.
[1]: https://en.wikipedia.org/wiki/HTTP_cookie