Answer:
Option A, most closely related to mammals
Explanation:
Insects like arthropods and molluscs have an open circulatory system and thus do have a distinguishable heart. Fish has two chambered heart. Reptiles have three chambered heart. Amphibians too have a three chambered heart.  
All mammals and fish have four chambered heart. The right and left sides of the chambers have restricted entry and hence remain intact from each other
Hence, option A is correct
  
 
        
             
        
        
        
Im going to have to go with C. they pass through channels in the cell membrane
        
                    
             
        
        
        
Pls post a
pick of the sphere
        
                    
             
        
        
        
Answer:
3. B. no new mating partners are available
7. D. best adaptations
8. C. survive and reproduce
Explanation:
Carrying capacity refers to the maximum population size of a species/population in a particular habitat. The carrying capacity depends on abiotic (e.g., shelter, water) and biotic factors (e.g., food, presence of mates). According to the evolutionary theory, individuals better adapted to their environments are more likely to survive and reproduce (i.e., produce more offspring) than other members of the same species. These 'better adapted' individuals will have more chances to pass their 'beneficial alleles' to the next generation.
 
        
             
        
        
        
Answer:
a mountain top
Explanation:
within most mountains tops the climate is cold