Questions

At least one black can be chosen in two ways from each box:
Now, probability of choosing at least one black ball from first box 

= 1/2 × [ (2C1× 2C1)/4C2 + 2C2/ 4C2 ]= 5/12

Probability of choosing at least one black ball from 2nd box
= 1/2 × [(4C1×12C1)/16C2 + 4C2/ 16C2] = 9/40

Final probability

= 5/12 + 9/40 = (50 + 27)/120 = 77/120

There are two major forms of democratic government.

I. Parliamentary
II. Presidential

The citizens elect the leaders in democratic government.

The main difference is legislative and executive branches.

Executive - head of government
Legislative - how laws are made

I. Parliamentary democratic government : (example - United Kingdom )

1. Parliament = Legislature (Laws)
2. Parliament controls the power
3. Head of government is a prime minister chosen by the legislature
4. Prime minister and cabinet are members of the legislature
5. Prime minister answers to the legislature (fusion of powers)
6. The government will stay in office for a specified period unless the prime minister loses support of the majority on an important vote.
7. If this occurs- the P.M. must resign and elections are held immediately.

II. Presidential democratic government : (example - United States of America)

1. The executive and legislative branches are separate bodies elected independently by the citizens.
2. Separation of Powers
3. There are checks and balances where each branch can overrule the other.
4. The president answers to the voters, not the legislature.
5. The people elect the president, and elections are held at set intervals.

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.