Find the error: \'Each of the students have submitted their assignment.\'

Choose the correct synonym of \'Happy\':

Choose the correct synonym of \'Ephemeral\':

Choose the one-word substitution for \'One who looks on the bright side\':

Piece of cake means:

Read the passage: \'Artificial intelligence has transformed healthcare through early disease detection, personalized treatment plans, and efficient drug discovery. However, concerns about data privacy and algorithmic bias remain significant challenges.\' What can be inferred?