"Furthermore, it is easier to realize."
Translation:De plus, il est plus facile à réaliser.
When the subject is "it", you may consider the pronoun refers to either a precise object (masculine or feminine in French) or a situation mentioned before (masculine by default).
With proper context, you would know what "it" stands for.
In any event, in this sentence, "it" is a real subject because "to realize" does not have a direct object.
- It/This/That is easier to realize = il/elle/c'est plus facile à réaliser (passive meaning = to be realized)
If "to realize" had a direct object, "it" would become impersonal and the French sentence would change:
- It is easier to realize this = Il est plus facile de réaliser ceci: "it" and "il" are impersonal subjects.
- Use de when facile/difficile is about the verb.
- Use à when facile/difficile is about a noun. In the Duolingo sentence, we don't know what "it" is exactly but we can assume it's a noun.
"Facile à, facile de On écrit facile de ou difficile de (faire quelque chose) quand facile se rapporte au verbe.
C'est facile de faire le café (It's easy to make coffee) = faire le café est facile (Making coffee is easy)
C'est difficile de se lever tôt (It's difficult to get up early) = se lever tôt est difficile (Getting up early is difficult)
On écrit facile à ou difficile à (faire quelque chose) quand facile se rapporte au nom.
C'est une recette facile à faire (It's a recipe that is easy to make or It's an easy-to-make recipe) = la recette est facile à faire (The recipe is easy to make)
C'est une leçon difficile à apprendre (It's a lesson that is difficult to understand or It's a difficult-to-understand lesson) = la leçon est difficile à apprendre" (The lesson is difficult to understand)
Sometimes "se rendre compte=réaliser" but not always. Like many words and expressions, both of these have a variety of possible definitions and meanings.
Both can mean "to become aware of something" but "se rendre compte" doesn't mean "to make something happen." It depends on the context.