use of subjunctive

Question

el cerebro se remodela literalmente en función de lo que hacemos cada día

Why isn't this 'de lo que hagamos?' As it doesn't refer to a specific activity and seems very hypothetical it looks the perfect candidate for a subjunctive.

Gracias

Silvia Píriz · Accepted Answer

Hola David L.
Good question! In this case, "lo que hacemos cada día" refers to the actual things we do on a daily basis, so Spanish uses the indicative because the speaker is talking about a known, real situation.
We typically use the subjunctive after lo que when the referent is unknown, hypothetical, non-existent, or yet to be determined:
Haré lo que me digas. (I will do whatever you tell me.)
Busco algo que me ayude a concentrarme. (I'm looking for something that will help me concentrate.)
But here the meaning is:
El cerebro se remodela literalmente en función de lo que hacemos cada día. = The brain literally reshapes itself based on the things we actually do every day.
Since those actions are presented as real and existing, hacemos (indicative) is the appropriate choice.
Saludos
Silvia