Which of the following is an instant messaging

Bus topology is also known by which one of the alternative names below?

Which of the following is NOT a type of firewall? 

What is the primary advantage of using an Object-Oriented Programming approach?

What is "serverless computing"?

Which protocol is commonly used for secure data transfer in cloud computing?

In C++, what mechanism is primarily used to achieve runtime polymorphism?

If receiver noise floor is 2 dB, signal-to-noise ratio is 3 dB then what is the receiver sensitivity?

Consider the following Java code snippet:

    import java.util.ArrayList;

    import java.util.Arrays;

Which data structure is most commonly used to efficiently implement a priority queue?

In pandas, what does df.groupby('A').agg({'B': 'sum', 'C': 'mean'}) return?