Concept:Chromosomes are thread-like structures present inside the nucleus that carry genes, and their number is fixed for each species.
Explanation:Option A is wrong because chromosomes of a species can differ in shape and size.
Option B is correct because every species has a constant chromosome number, such as
46 chromosomes in humans.
Option C is wrong because chromosomes are located inside the nucleus, not scattered in the cytoplasm.
Option D is wrong because ribosomes found on outer membranes belong to the rough endoplasmic reticulum, not chromosomes.
Answer:B. The number present in a species is constant