Minimize the noise power at the system output

Question

Assignment:

1. If we want to minimize the noise power at the system output, is it more convenient to use a cascade of N passive two-port networks each at temperature T₁ and gain g₁, or a unique passive two-port network at temperature T₁ and gain (g₁) N?

2. If our aim is to minimize the noise power at the system output, is it more convenient to use a single amplifier with noise figure F and gain g, or the cascade of N amplifiers each with noise figure F and total (of the cascade) gain g?