Answer:
Viruses are like hijackers. They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. This can kill, damage, or change the cells and make you sick. Different viruses attack certain cells in your body such as your liver, respiratory system, or blood.
Explanation:
Viruses tend to target specific tissues (cells) in the host.
For example, the influenza virus has a predilection for the respiratory tract, hepatitis viruses target the liver, polio virus targets the motor neurons of the spinal cord and rotavirus multiplies in the gut. Symptoms of a viral infection may be subtle and nonspecific or specific and suggestive of the causative agent.
Dengue virus, Ross river virus, measles and rubella infections are associated with fever and a widespread red rash, chicken pox and herpes simplex viruses are associated with blistering, often localized, rashes; and hepatitis viruses cause liver damage and jaundice.
Bacteria tend to be less tissue-specific and non-discriminatory than viruses and can cause a variety of infections once they have invaded the host.
These bacterial infections are often manifested by the presence of pus wherever the bacteria settle, and systemic symptoms such as fevers, chills, pain, swelling and loss of function occur when bacteria invade and multiply.
 
        
             
        
        
        
Answer:
The correct answer is- 4:0
Explanation:
Marfan syndrome is a genetic problem which affects the connective tissue in the body. The trait for this disease is autosomal dominant which means even one abnormal copy of this gene in the offspring or individual is sufficient to cause this syndrome.
Let S is the allele that is dominant for this syndrome and s is recessive. So if a cross between homozygous dominant(SS) and heterozygous individual (Ss) occurs than all the offspring would have this syndrome.  
                                    S      s
                               S  SS   Ss
                               S  SS   Ss
Therefore all 4 offspring would have at least one dominant allele which is sufficient to cause this syndrome. So the phenotype ratio would be 4:0.
                        
 
        
             
        
        
        
Answer: B
Explanation:
"Furthermore, ectomycorrhizal fungi can slow down decomposition, a natural process that returns carbon from forest soils back to the atmosphere. In these ways, ectomycorrhizal fungi enhance the ability of forests to keep carbon locked up in trees and soils, and out of the atmosphere." (http://www.bu.edu/articles/2018/4-things-to-know-about-fungi-climate-warriors/)
 
        
                    
             
        
        
        
Answer:
B. phagocytes 
Explanation:
Phagocytosis is a process wherein a cell binds to the item it wants to engulf on the cell surface and draws the item inward while engulfing around it. The process of phagocytosis often happens when the cell is trying to destroy something, like a virus or an infected cell, and is often used by immune system cells.
 
        
                    
             
        
        
        
The ocean and the present atmosphere themselves are not leftovers from the original atmosphere of Earth. However, they do contain components within them that give us and scientists ideas of what Earth's past atmosphere was like. 
Some example include:
1) Ice cores - scientists may go to Antartica or Alaska and stick this metal tube into the ice to remove what is known as an "ice core". This is then taken back to the lab for analysis. So what happens is that this ice as we know is constantly melting and freezing with different seasons and climate change. So, when the ice starts to crystallize, particles like carbon dioxide, sulfur etc may get trapped as bubbles in the ice. This is what scientists look for in ice coring and this is how they know that Carbon dioxide levels were relatively high back then (Not as high compared to now). 
2) Ocean sediment cores - this is the exact same process of the ice cores except they take cores of sediments (esspecially calcium carbonate that contains oxygen). As you know, CaCO3 is found in the exoskeletons of organisms that die and build up on the ocean floor. 
Those are some of the main ways that the present atmosphere and oceans have leftovers from the original atmosphere of Earth. 
Hope that helped!