La profesora de biología explicó que una raíz sana ayuda a que la planta florezca.

Because profesora is the feminine form of profesor. Spanish nouns referring to people often change depending on gender:

• el profesor = the male teacher
• la profesora = the female teacher

The article also changes to match:

• la profesora
• el profesor

So the sentence specifically tells us the biology teacher is female.

In Spanish, school subjects are very often expressed with de:

• profesora de biología = biology teacher
• profesor de historia = history teacher
• profesora de matemáticas = maths teacher

This is the normal Spanish way to say what subject someone teaches. English often uses a noun directly before another noun, but Spanish usually links them with de.

The accent mark shows where the stress goes: bi-o-lo-GÍ-a.

Without the accent, Spanish pronunciation rules would suggest a different stress pattern. So the written accent helps you pronounce it correctly.

The same kind of thing happens in many words ending in -ía, such as:

• geografía
• filosofía
• economía

Explicó is the preterite form of explicar, meaning explained.

• explica = explains / is explaining
• explicaba = was explaining / used to explain
• explicó = explained

In this sentence, explicó presents the explanation as a completed action in the past.

Here, que means that.

• explicó que... = explained that...

It introduces the content of what was explained. This is very common in Spanish:

• Dijo que... = He/She said that...
• Pensó que... = He/She thought that...
• Explicó que... = He/She explained that...

In English, that is sometimes optional, but in Spanish que is usually kept.

Spanish often uses an article where English might sometimes leave it out.

• una raíz sana = a healthy root

The article una shows we are talking about a healthy root in a general sense. It sounds natural and complete in Spanish.

Also, raíz is feminine, so it takes feminine words with it:

• una raíz
• raíz sana

In Spanish, adjectives often come after the noun:

• una raíz sana = a healthy root
• una planta grande = a big plant
• un libro interesante = an interesting book

That is the normal position for many descriptive adjectives.

If you put an adjective before the noun in Spanish, it can sometimes change the tone or emphasis, but raíz sana is the standard, neutral order.

This is an important structure. Ayudar can be followed in different ways depending on what comes next.

If the same subject does both actions, Spanish often uses an infinitive:

• La luz ayuda a crecer la planta.
• El ejercicio ayuda a dormir mejor.

But when a new clause with its own subject follows, Spanish often uses:

• ayudar a que + subjunctive

So here:

• una raíz sana ayuda a que la planta florezca

There are two different elements:

• una raíz sana helps
• la planta blooms

That is why a que is used.

Because after ayuda a que, Spanish normally uses the subjunctive.

The sentence expresses that one thing helps make another thing happen:

• una raíz sana ayuda a que...
• a healthy root helps the plant bloom

This kind of idea—helping, causing, influencing, making possible—often triggers the subjunctive in the clause after que.

So:

• florezca = present subjunctive of florecer

It is not a statement of plain fact like florece. It is part of a structure showing effect or influence.

This is a very common thing that confuses learners.

The main verb is past:

• explicó = explained

But florezca stays in the present subjunctive because the sentence is reporting a general idea or fact that is still valid:

• The teacher explained that a healthy root helps the plant bloom.

The blooming is not being located as a finished past event. It is being presented as a general process or result.

If the sentence were framed differently and clearly placed in a past context, other forms could appear, but in this sentence florezca is the natural choice.

La planta refers to the plant as the plant involved in this process. It sounds specific within the statement.

Spanish often uses the definite article in general explanatory statements when talking about something understood in context:

• la planta florezca = the plant blooms

If you said una planta, it would sound more like a plant in a less specific or more generic sense. Here, la planta fits the idea that the root belongs to the plant being discussed.

Florezca is the first-person singular and third-person singular form of the present subjunctive of florecer.

The infinitive is:

• florecer = to bloom / to flower

Present subjunctive forms include:

• yo florezca
• tú florezcas
• él/ella florezca
• nosotros florezcamos
• vosotros florezcáis
• ellos florezcan

In this sentence, it matches la planta, which is third-person singular:

• la planta florezca

Yes, in this sentence ayuda a que la planta florezca is the more natural and clearer option.

Why? Because Spanish strongly prefers a que + subjunctive when the action after ayudar has its own subject:

• una raíz sana ayuda a que la planta florezca

Using ayuda a florecer la planta is much less natural here. It sounds awkward because la planta is the subject of florecer, and Spanish usually handles that relationship better with a que + subjunctive.

So for learners, a good rule is:

• ayudar a + infinitive when there is no new subject
• ayudar a que + subjunctive when there is a new subject