Answer:
Option D, a test for the presence of cells that contain DNA
Explanation:
As we know all living organisms are made up of cells and DNA is the basic genetic material that codes for protein and traits with an organism. If even a single cell with DNA is detected on the extraterrestrial planet then it will be clear that it has life on it or the environmental conditions are favorable to support life. Cells are microscopic and hence can be seen through microscope which can be installed easily on a probe. 
Hence, option D is correct
 
        
             
        
        
        
Answer:
A species refers to the group of similar organisms that can interbreed to produce a viable offspring. For example, <em>Homo sapiens </em>is a species of humans, <em>Panthera leo </em>refers to the species of lions et cetera.
In contrast, a population in ecology refers to the group of organisms of the same species living in a particular area. For example, the deer population in a forest, human population in a town et cetera.
For example, <em>Aptenodytes patagonicus </em>refers to a species of penguins but number of penguins of the same species living in a particular area would make up a penguin population of that area.
 
        
             
        
        
        
Father because you inherit traits from your mother and recessive sex linked traits from your father.