During the early stages of meiosis, two chromosomes in a homologous pair may exchange segments, producing genetic variation in sex cells. this process of exchange is called a) transcription. b) crossing over. c) nondisjunction. d) genetic shuffling.

The correct answer is option B, that is, crossing over.  

Crossing over or chromosomal crossover refers to the interchange of genetic substance between the two homologous chromosomes non-sister chromatids, which leads to the formation of recombinant chromosomes at the time of sexual reproduction.  

It takes place in the pachytene stage of prophase I of meiosis at the time of a procedure known as synapsis.  

✿   this landform has a high elevation and a high relief

✿   this landform is a mountain

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.