A raiz está sob a planta; o caule tem um galho.

Portuguese nouns have grammatical gender, so you usually learn each noun together with its article:

• a raiz = the root
• a planta = the plant
• o caule = the stem
• um galho = a branch

Here:

• raiz is feminine, so it takes a
• planta is feminine, so it takes a
• caule is masculine, so it takes o
• galho is masculine, so it takes um

This gender is a grammar feature, not necessarily something logical. The best habit is to memorize nouns with their article.

Portuguese has two main verbs for to be: ser and estar.

• ser is used for identity, permanent characteristics, definitions, origin, etc.
• estar is used for location, temporary states, and conditions.

In A raiz está sob a planta, the sentence is talking about where the root is located, so estar is the correct choice.

A useful shortcut:

• Where something is → usually estar
• What something is → often ser

Sob means under, beneath, or below.

So:

• sob a planta = under the plant

In Brazilian Portuguese, sob is correct, but it sounds a bit more formal or written. In everyday speech, people often say:

• debaixo da planta
• embaixo da planta

These are more common in conversation.

So this sentence is grammatical and natural enough, but sob has a slightly more formal or textbook-like feel.

Some Portuguese prepositions contract with articles:

• de + a = da
• em + a = na
• a + a = à

But sob normally does not contract with the article. So you simply say:

• sob a planta
• sob o caule

No contraction is needed.

No. Planta can have more than one meaning in Portuguese, depending on context. Common meanings include:

• plant
• floor plan
• sole of the foot in some contexts

In this sentence, because of raiz, caule, and galho, it clearly means plant.

Not necessarily. In sentences like this, Portuguese often uses the singular to talk about a part of something in a general, descriptive way.

So A raiz está sob a planta can be understood as a simple description of the root as a part of the plant, not necessarily a claim that there is exactly one literal root.

This is similar to how language sometimes describes body parts or plant parts in the singular for general explanation.

Yes. Tem is the third-person singular of ter, which usually means to have.

So:

• o caule tem um galho = the stem has a branch

This expresses possession or inclusion: the stem includes/has a branch.

In English, we might sometimes phrase this differently depending on context, but in Portuguese, ter is very common for this kind of relationship.

It can mean either, depending on context.

• um can be the indefinite article a/an
• um can also be the number one

In this sentence, the most natural reading is a branch, not an emphasized one branch.

If the speaker wanted to stress the number, context or intonation would usually make that clearer.

Not naturally in this exact structure.

• há / existe mean there is / there exists
• tem here means has

So:

• O caule tem um galho = The stem has a branch

If you changed it to Há um galho no caule, that would mean:

• There is a branch on the stem

That is possible, but it is a different sentence structure and emphasis.

Both can relate to branches, but they are not always interchangeable.

• galho usually means a physical branch, especially a woody branch
• ramo can also mean branch, but it can sound more like a bough, sprig, or even a figurative branch, as in a field of study or business area

In a basic plant-parts sentence, galho is a very natural choice for branch.

A simple approximation for Brazilian Portuguese:

• raiz ≈ ha-EEZ
  The r at the beginning is like an English h in many Brazilian accents.

• caule ≈ KOW-lee
  The first part rhymes roughly with cow.

• galho ≈ GAH-lyoo
  The lh sound is like the lli in million for many English speakers, though not exactly the same.

The most important tricky sound here is lh in galho. It is a very common Portuguese sound.

Yes, you could use a period instead.

The semicolon in:

• A raiz está sob a planta; o caule tem um galho.

links two closely related complete clauses. It shows that the ideas belong together.

A period would also be fine:

• A raiz está sob a planta. O caule tem um galho.

A comma would be less standard here, because both parts are full independent clauses.

Yes, it is understandable and grammatical, especially in a teaching or descriptive context.

That said, for natural everyday Brazilian Portuguese:

• sob may sound a bit formal
• a science or school text might prefer more precise wording depending on the exact botanical meaning

But as a learner sentence, it works well because it clearly teaches:

• articles
• noun gender
• estar for location
• ter for possession
• plant vocabulary

Yes, Portuguese allows more flexibility in word order than English.

For example:

• A raiz está sob a planta.
• Sob a planta está a raiz.

Both are possible.

The first is the most neutral and straightforward.
The second sounds more marked or literary, because it emphasizes the location first.

For beginners, the original word order is the safest one to use.