niche-segments是什么意思

英语翻译
Apple targets segments consist of professionals,students,corporate users,entrepreneurs.
我想知道那个 corporate users具体指什么呢
和 entrepreneurs 有什么区别呢
还有 targets segments 有这个用法么?

蓝精灵村庄 Add 3 segments of stone wall to the village.
这个任务都做了三天了.

英语翻译
A gene is a set of segments of nucleic acid that contains the information necessary to produce a functional RNA product in a controlled manner.They contain regulatory regions dictating under what conditions this product is made,transcribed regions dictating the sequence of the RNA product,and/or other functional sequence regions.The physical development and phenotype of organisms can be thought of as a product of genes interacting with each other and with the environment,and genes can be considered as units of inheritance

Visual Basic:Which of the following segments will call the method ReadData four times?
Which of the following segments will call the method ReadData four times?_____
A) Dim k As Integer
k = 1
While k 4
ReadData()
k = k + 1
End While
B) Dim i As Integer
i = 0
While i

英语翻译
A gene is a set of segments of nucleic acid that contains the information necessary to produce a functional RNA product in a controlled manner.They contain regulatory regions dictating under what conditions this product is made,transcribed regions dictating the sequence of the RNA product,and/or other functional sequence regions.The physical development and phenotype of organisms can be thought of as a product of genes interacting with each other and with the environment,and genes can be considered as units of inheritance

英语翻译
three healthy
first order root segments 2cm long) were chosen to insert into three
different rhizotrons built for this purpse.这句话中的rhizotron是什么意思?