A mental warm-up.

Updated table:

8 - Bayazet, Oldboy, Valenok
5 - zloy romantik, Grizvald, nik312, Yostairs
4 - Defiant, FireToSky, Juristis
3 - Horn, Gur, redwhait
2 - kalababa, The_, aka.Ward3n

Added 2 minutes ago
Number of people who answered individual questions correctly:

1 - 1
2 - 1
3 - 3
4 - 1
5 - 1
6 - 2
7 - 5
8 - 9
9 - 3
10 - 3
11 - 4
12 - 4
13 - 0
14 - 4
15 - 2
16 - 4
17 - 5
18 - 1
19 - 0
20 - 4
21 - 0
22 - 6
23 - 5
24 - 0
25 - 3

Added 13 minutes ago
Here is a table with adjustments for the difficulty of the questions. For a question answered by only 1 person, 5 points are awarded; 2 people - 4 points; 3 people - 3 points; 4 people - 2 points; 5 or more - 1 point.

21 - Bayazet
19 - Oldboy
16 - Valenok
15 - zloy romantik
11 - nik312
9 - Grizvald, Defiant
8 - FireToSky, Juristis
7 - Yostairs
6 - redwhait
5 - Horn, Gur
4 - The_
2 - kalababa, aka.Ward3n

Added 9 hours 40 minutes ago
Hint for question 21 - relatives are representatives of the same biological species. And you don't need to know biology at all to answer this question.