Answer:
Density is an intrinsic physical property of minerals that relates to the composition of the mineral and to the pattern in which the mineral’s atoms are arranged. 
 
        
             
        
        
        
Answer:
d. vary and change for both males and females from culture to culture
Explanation:
Gender roles vary for both females and males across cultures. This can be observed in the way some societies are patriarchal and some are matriarchal. For example: in many Asian cultures, traditionally males head the families. It's their responsibility to engage in outside work and take important decisions for the family while women take care of household chores. This is reversed in some cultures like that present in Meghalaya, India. Here women are dominant figures in households. They inherit property, give their family name to children and after marriage the man comes to live with the woman's family. Hence gender roles are variable culture to culture.  
 
        
             
        
        
        
Answer:
In double-stranded DNA, the molecular double-helix shape is formed by two linear sugar-phosphate backbones that run opposite each other and twist together in a helical shape. The sugar-phosphate backbone is negatively charged and hydrophilic, which allows the DNA backbone to form bonds with water.
 
        
             
        
        
        
Answer:
during the Cambrian Period of the Paleozoic Era.
Explanation:
The Paleozoic is the earliest era (of three) of the Phanerozoic Eon and is composed of six geologic periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (in that order from earliest to the latest). Fish first appeared about 530 million years ago during the Cambrian explosion.