Мы взяли этого бездомного котёнка из приюта, потому что он сразу пошёл к людям.

Взяли is the perfective past of взять (to take). Russian often uses the perfective when talking about a completed action: they took the kitten from the shelter, and that action is presented as a whole event.

• взять / взяли = to take, took once, completed
• брать / брали = to take, be taking, used to take, or take repeatedly

So here Мы взяли... means we took / adopted this kitten as a completed action, not an ongoing or repeated one.

Because котёнок is the direct object of взяли, so it goes into the accusative case.

For masculine animate nouns, the accusative singular usually looks like the genitive singular. So:

• nominative: котёнок
• accusative: котёнка

This happens because the kitten is a living being, so Russian treats it as animate.

Compare:

• Я вижу стол = I see a table (inanimate, accusative = nominative)
• Я вижу котёнка = I see a kitten (animate, accusative = genitive)

Because in Russian, adjectives, pronouns, and nouns must agree in case, number, gender, and animacy.

Here the whole phrase is the direct object, and since котёнок is masculine singular animate in the accusative, the other words must match it:

• этот → этого
• бездомный → бездомного
• котёнок → котёнка

So the entire phrase is aligned grammatically:

• этого бездомного котёнка = this homeless kitten

Yes, it does look like genitive, and that is exactly what often confuses learners.

For masculine animate singular, the accusative form of этот is the same as the genitive form:

• nominative: этот
• accusative masculine animate: этого
• genitive masculine/neuter: этого

So in this sentence, этого is functioning as accusative, not genitive.

The preposition из means out of / from and requires the genitive case.

So:

• приют = shelter
• из приюта = from the shelter

This is a very common pattern:

• из дома = from the house
• из школы = from school
• из России = from Russia

Both can mean from, but they are used in different situations.

• из = from inside something, out of something
• с = from off a surface, or from an event/place in some contexts

So here из приюта is natural because a shelter is understood as an institution/building that you take the kitten from/out of.

Compare:

• из магазина = from the store
• со стола = from the table
• с работы = from work

Пошёл is the perfective past of пойти, which often means started going / went. In context, it means the kitten went over to people.

A few useful contrasts:

• шёл = was going, went on foot, ongoing action
• пошёл = started going / went
• подошёл = came up to, approached

So он сразу пошёл к людям suggests that the kitten immediately moved toward people.
If you said сразу подошёл к людям, that would focus more strongly on the idea that he came right up to them.

Both can work in some contexts, but пошёл к людям is very natural here.

The preposition к means to / toward and takes the dative case.

The noun here is:

• nominative plural: люди = people
• dative plural: людям = to people

So:

• к людям = toward people / to people

This is a common pattern:

• к маме = to mom
• к другу = to a friend
• к детям = to the children

Because люди is an irregular plural form of человек (person).

Its plural case forms are built from люд-:

• nominative plural: люди
• genitive plural: людей
• dative plural: людям
• instrumental plural: людьми
• prepositional plural: о людях

So к людям is just the correct dative plural form of this irregular noun.

Russian often can omit subject pronouns, but it depends on clarity and style.

Here он refers back to котёнок. Including it makes the sentence very clear:

• ..., потому что он сразу пошёл к людям.

Without он, the sentence would sound less natural here because after потому что, it helps to state the subject explicitly. Russian does omit pronouns quite often, but not as freely in every context as, for example, Spanish or Italian.

So он is natural and clear.

Потому что is the standard everyday way to say because.

• потому что = because
• так как = since / because, often a bit more formal or bookish
• потому by itself does not mean because in the same way

So this sentence uses the most normal conversational option.

Examples:

• Я ушёл, потому что устал. = I left because I was tired.
• Так как было поздно, мы ушли. = Since it was late, we left.

Сразу means right away, immediately, or straightaway.

In this sentence it shows that the kitten went to people without hesitation. That detail helps explain why they decided to take him.

So:

• он сразу пошёл к людям = he immediately went toward people

It often adds the idea of something happening at once, not after waiting.

Russian word order is fairly flexible, but different orders change the focus or emphasis.

The given sentence is neutral and natural:

• Мы взяли этого бездомного котёнка из приюта, потому что он сразу пошёл к людям.

Possible rearrangements are grammatically possible, for example:

• Мы взяли из приюта этого бездомного котёнка...
• Потому что он сразу пошёл к людям, мы взяли этого бездомного котёнка из приюта.

These versions shift emphasis a bit, but the original sounds very standard and straightforward.

In this context, взяли very naturally implies took in or adopted, even though the basic verb literally means took.

Russian often uses взять in this kind of context:

• взять котёнка
• взять собаку из приюта

Depending on context, that can mean to adopt, to take home, or to take in.

So the literal verb is took, but the real-life meaning is often closer to adopted.