Learn Hardcore German: Manche Aufgaben betreffen nur die Leiterin, andere betreffen das ganze Team. - Some tasks concern only the female leader; others concern the whole team.

The verb betreffen takes a direct object in the accusative case.
die Leiterin here is accusative singular feminine (it looks the same as nominative).
das ganze Team is accusative singular neuter (also looks the same as nominative).
Example: Diese Aufgaben betreffen den Leiter / die Leiterin / das ganze Team.

Why is the verb form betreffen and not betrifft?

The subject is plural: Manche Aufgaben, so the verb is 3rd‑person plural: betreffen.
In the second clause, andere stands for andere Aufgaben (also plural), so you again use betreffen.
Singular would be: Eine Aufgabe betrifft nur die Leiterin.

What does betreffen mean compared with angehen, gelten (für), or sich beziehen auf?

betreffen = to concern/affect (takes a direct object). Neutral and common: Das betrifft mich/das Team.
angehen = to concern (often with pronouns, a bit more colloquial): Das geht mich nichts an.
gelten (für) = to apply (to) rules/conditions: Die Regel gilt für das ganze Team.
sich beziehen auf = to refer/relate to (more formal): Die Frage bezieht sich auf den Bericht.

Why is andere used without repeating Aufgaben?

German often omits a repeated noun if it’s clear from context. andere here means andere Aufgaben.
This is a normal ellipsis to avoid repetition.

Why andere and not anderen?

As a standalone plural subject (nominative), the form is andere.
anderen appears as:
- dative plural: mit anderen
- with a definite article: die anderen Aufgaben
- or in other cases requiring -n endings.
Here, andere = “others” (subject), so nominative plural is correct.

Why is there a comma between the two clauses even without und/aber?

German allows (and typically expects) a comma between two independent main clauses that are simply juxtaposed.
A semicolon is also possible: …; andere …
So Manche …, andere … is standard punctuation.

Where should nur go, and can I move it?

nur normally goes directly before the element it restricts: betreffen nur die Leiterin (“affect only the manager”).
You can front the restricted element for emphasis: Nur die Leiterin betreffen manche Aufgaben (marked but grammatical).
betreffen die Leiterin nur is possible but sounds clunky; placing nur before its focus is best.

Could I say die anderen instead of andere?

Yes: …, die anderen betreffen das ganze Team.
Nuance:
- andere = “other(s)” in general, unspecified.
- die anderen = “the other (remaining) ones,” i.e., the rest of the set you have in mind.
Both can work; die anderen highlights a clear split into two groups.

Is Leiterin the female form? Could it be confused with “ladder”?

die Leiterin = female leader/manager.
der Leiter = male leader/manager.
die Leiter (same spelling as the feminine article) = “ladder” (a different noun). Context and the -in ending make Leiterin unambiguously a person.

Why use the definite article die Leiterin and not just Leiterin?

German usually requires an article with singular count nouns. Bare Leiterin would sound incomplete here.
You can omit the article mainly after sein/werden/bleiben or with als for roles: Sie ist Leiterin. / Er arbeitet als Leiter.
In the given sentence, die Leiterin is the normal choice; eine Leiterin would be possible if you meant “a (certain) manager.”

Why das ganze Team and not das gesamten Team? What about gesamte?

After a definite article (das), the adjective takes the weak ending -e in neuter nominative/accusative singular: das ganze Team.
das gesamte Team is also correct; gesamt is a near-synonym of ganz here.
das gesamten Team is wrong.
Compare: with an indefinite article you’d get ein ganzes Team; masculine accusative shows -en: den ganzen Tag.

Is Team singular or plural in German?

Team is neuter singular: das Team. It behaves like a singular noun (e.g., Das Team ist motiviert.).
In the sentence it’s an object, so no agreement issue with the verb arises.

Can I drop the second betreffen to avoid repetition?

Yes. This “gapping” is idiomatic: Manche Aufgaben betreffen nur die Leiterin; andere das ganze Team.
A semicolon is especially clear here; a comma is also acceptable.

Is manche used only in the plural? What about the singular mancher?

In everyday German, manche is mainly plural: Manche Aufgaben …
The singular exists but is more literary: Manch eine Aufgabe betrifft nur die Leiterin. (“Many a task …”)

Does betreffen ever take a preposition like für?

No. betreffen is directly transitive: etw./jdn. betreffen (+ accusative), no preposition.
If you mean “apply to,” use gelten für: Die Regel gilt für das ganze Team.