Read the following text about some of the Zika’s features and observe the conjunction "if" in bold:

 

The severity varies, but it can be deadly if the brain is so underdeveloped that it cannot regulate the functions vital to life.

Disponível em: . Acesso em: 14 mar. 2017.

 

Considering its meaning, "if" could be replaced by the following conjunction:

• also

• when

• then

• besides

• unless