Why is it not always necessary to include a subject pronoun before the verb in Spanish?

Unit 4 test

1.B
2.C
3.D
4.A
5.C
6.D
7.D
8.C
9.A
10.C
11.B
12.B
13.A
14.B
15.D
16.D
17.C
18.A
19.A
20.B
THESE ARE CORRECT. i JUST TOOK THE TEST AD GOT A 100

The reason is that the ending of the conjugated verb "tells" the subject.

o - yo
s - tú
vowel (a, e) = él, ella, Usted
-mos = nosotros/nosotras
-is = vosotros/vosotras

-n = ellos, ellas, ustedes
Above are the ending signals just for the Present Tense, as an example.

Sra

you are 100% correct thank you so much

Thank you so much anonomys! There still the same answers even in 2019 lol

thanks you~ <3

Omg poggers still 100% correct in november 2020

That was such a bad and unclear answer wtf

Lol I'm on the same test omg they are XD

2021

same in 2021 lol :)