Spanish speakers frequently pronounce, b, as a sound intermediate to b and v. It is a sound that doesn't exist in English.
LOL.. That was my first guess and I was like "What!? That does not sound right!" I was somewhat happy I got it wrong.
Baja = both an adjective and a verb. As an adjective, to be "short." As a verb (bajar), it means literally "to make shorter" .. or, in more approximate English, where we go from a higher altitude to a lower altitude. WR lists: take down, fall, drop, unzip, come down, go down, stoop, descend, lower, even download. Another instance of Spanish simplifying things, as someone pointed out in another discussion thread. There is also the word "abajo," which is more downwards including downhill, down stairs, below, etc.
"Under" would be"debajo de." And "bajo" would refer to "first floor, ground floor" as well as being the male variant of the adjective "Baja". Bajo is also: lower, below, beneath, etc.
If anyone wants to add to that or correct me, feel free!
When bajar* means go o pass from a place to another lower** is a intransitive verb and is used with complements of origin (de, desde).
Bájate de la bicicleta. Baja los platos de la estantería.
Sometimes it is formed with a complement begining with por, that express the place that is gone over during the acdescent.
Él bajó por las escaleras.
If you want to say that something is under another thing you use the word bajo. El gato está bajo la mesa. The cat is under the table.
baja can be an adjetive, a sustantive and a verb. Like a verb (the exercise) is get off. The verb is bajar. Yo bajo, tú bajas, él ella baja, nosotros bajamos, vosotros bajais, ellos bajan.
Like an adjetive it can be use in many cases.
Ella es más baja que yo. She is shorther than I.
Mi oficina está en una planta baja. My office is a lower flour.
I really believe this sentence needs to be reflexive (Ella SE baja del caballo) in order to mean: "She gets off the horse." Without the "se," it means "She lowers/drops/falls/goes down/descends from the horse." These may be awkward ways to say "gets off" or maybe it's some kind of accepted idiom where I'm missing the point, but compare the meanings of bajar and bajarse here: http://www.spanishdict.com/translate/bajar and form your own opinion.
You can use whatever you want for to get off, bajar or bajarse
and «Subir(se) and bajar(se) occur with the following four kinds of senses... getting on or off a vehicle. The rate of se - marking in each category was around 30% in spoken data and 10% in written» see more in:
Lesson: Use a dictionary for further explanation. Please can we clean up some of the sexual connotations - not being a prude I laughed too at the literal translation but we have to be mindful - Don't children and teachers use Duolingo. Yeah, I know probably "children" wrote the inappropriate comments but still...
Yo (me) bajo del caballo Tú (te) bajas del caballo Él/ Ella( se) baja del caballo Nosotros/as (nos) bajamos del caballo Vosotros/as (os) bajáis del caballo Ellos/as ( se) bajan del caballo Preposition Under, below - bajo , debajo de. Your translation would be: Ella está bajo el/ or/ debajo del caballo.Here, The pronouns ( me,te,se,os)are optional.they intensify the action of the verb. Example: Yo Como un tomate or Yo ( me) Como un tomate - I eat a tomato. http://www.wordreference.com/es/en/translation.asp?spen=bajar