The visceral and parietal pleural membranes are normally held together by
a. loose connective tissue.
b. dense connective tissue.
c. decreased pressure in the pleural cavity.
d. surfactant in the pleural cavity.
e. elastic connective tissue.

C) decreased pressure in the pleural cavity.

Explanation:

The pleura is a membrane that surrounds the lung and consists of two membranes, the parietal and the visceral, which are continuous in the hilum region of the lung. The parietal and visceral membranes delimit, for each lung, an independent cavity fully lined by the mesothelium. Typically, this pleural cavity is virtual, containing only a thin layer of lubricating fluid (pleural fluid), allowing smooth sliding of these two membranes during respiration, preventing friction between the visceral and parietal mesothelium.

The visceral and parietal pleural membranes are usually held together due to decreased pressure in the pleural cavity.

high growth (apex)

the answer to the blank provided is “an autosomal gene that is required for the expression of genes on the x chromosome”.

testis-determining factor, abbreviated as td, which is more popularly known as sex-determining region y or sry protein, is a dna-binding protein or  gene-regulatory protein/transcription factor, encoded by the  sry gene. it is the gene responsible for the initiation of male gender determination in humans.