Breakdown of Энергичные люди бывают здоровыми, причём у них сильный иммунитет.
они
they
люди
people
у
at, by
сильный
strong
Questions & Answers about Энергичные люди бывают здоровыми, причём у них сильный иммунитет.
What exactly does причём add to the sentence, and could I just use и instead?
Причём (moreover, and what's more) doesn't just connect two equal facts like и (and) does. It introduces a supplementary, often amplifying detail that builds upon the first statement. Using и is grammatically fine, but причём emphasizes that their strong immunity is an important bonus or a deeper manifestation of their general health.
Since this lesson covers both причём and притом, could I use притом in this sentence?
Yes, they are very similar and often interchangeable when adding extra information. However, причём is a perfect fit here because it typically introduces a detail that naturally develops or clarifies the first thought (being healthy relates directly to strong immunity). Притом is often preferred when adding a more independent accompanying fact.
Why use бывают here instead of just dropping the verb, as we normally do for 'to be' in the present tense?
Dropping the verb (like in Энергичные люди — здоровые) would state an absolute, constant fact: 'Energetic people are healthy.' Using бывают (the frequentative form of the verb to be) adds the nuance of 'tend to be' or 'are usually.' It shows a recurring state rather than an absolute rule.
Why is the adjective здоровыми in the instrumental case?