Is this sentence grammatically correct, and what should I do to fix it?

Places with undifferentiated highlands always have a high physiological density. Places with humid low-latitude climate almost always have at least a medium density

I’d make it two seperate sentences.

@SpatzieLover That does help with the wordiness, but I will probably end up throwing in a phrase that helps to make the two sentences flow better.

Also, is there anything wrong with the wording of the second sentence? I think it sounds weird with the singularity of “climate” compared to the plurality of “places” and “always have”. Maybe my perception of the error has to do with the first sentence, which has a very similar structure, but does not have this conflict.

Your sentence is contrasting the attributes of two things that are not necessarily parallel constructions. The first part is a physical description, the second describes the climate of another physical description. What is the climate of an undifferentiated highland?

@zenvelo The thing that I am looking at (a map of different climate zones) describes undifferentiated highlands as “cold due to elevation, and mountainous regions of variable climate.” Should I word the sentences differently to indicate that they are in fact supposed to be parallel constructions?

It sounds as if the wording of your source material needs some work. It describes undifferentiated highlands as cold (a relatively constant climate condition) due to elevation then in the same breath says they are mountainous and have variable climates. Mountainous is not undifferentiated. Climates in mountainous zones differ substantially based on elevation. Little wonder you are confused.

In the first place, I think you’re talking about “altitude”, and not latitude. Aside from that, I think some explanation is called for in terms. What, exactly, is an “undifferentiated highland”? What is “physiological density”?

@PhiNotPi Consider using the climate differences to result in different densities. Then clarify that certain highlands/altitudes are cool, other terrain is more humid.

Notice that everyone is okay with your grammar, we’re just have comments on clarifying what you are trying to convey.

@CWOTUS Actually, I am talking about low latitude, as in places close to the equator. This really isn’t meant for a general audience; my audience will know what I am talking about. I guess my sentence really doesn’t make too much sense if you don’t have a clue what I am talking about.

In that case the sentence is grammatically correct, just awkward and indefinite. “Low latitude” meaning how close to the Equator? There’s no universally accepted agreement among geographers about how low is low, is there? Likewise “high” and “medium” density.

@CWOTUS I know that what I am talking about is indefinite, but in this case I really don’t have a choice.

Due to their geographical predispositions, the areas with undifferentiated highlands will always include high physiological densities such as coldness due to elevation and mountainous regions of variable climate. On the contrary, geographical areas with humid low-latitude climates always include at least a medium physiological density.

@linguaphile That doesn’t really make sense if you know what physiological density is. It is, guess what, actually the number of people per unit of arable farmland. I can’t really blame you for not knowing.

It doesn’t seem like much of a contrast if one has a high density while one has “at least a medium” density. Why are you using the word “while” which kind of implies a contrast.

@PhiNotPi Aha… yep, I didn’t know—I was going by what I read in the Q and answers. Okay… let me try again…

Due to their geographical predispositions, the areas with undifferentiated highlands will always include high physiological densities as a result of the impact from variable climates. On the contrary, geographical areas with humid, low-latitude climates always include at least a medium physiological density.

Better?

I would do what @SpatzieLover said.

The first part of the sentence sounds fine. The second part though; ”...almost always…” and ”...at least…” sound a bit weird together, I think a single word for one or both of these would make your sentence sound more assured and definite, if that makes sense.