Study the diagram of the heart and answer the questions that follow. Write down the LETTER and NAME of the blood vessel that transport blood to the lungs.

Here are the answers to your questions:

1.4.5
There are gaps in the fossil record for several reasons:

• Not all organisms fossilize; specific conditions are required for fossilization, such as rapid burial and the presence of hard parts.
• Many fossils have been destroyed by geological processes like erosion, metamorphism, or tectonic activity.
• Many fossils are yet to be discovered and remain buried deep within the Earth.

1.4.6
Other places where fossils can be formed, besides sedimentary rocks, include:

• Amber (fossilized tree resin)
• Ice (e.g., frozen mammoths)
• Tar pits (e.g., La Brea Tar Pits)
• Volcanic ash

1.5.1
The blood vessel that transports blood to the lungs is C, the pulmonary artery.

1.5.2
Blood vessel A is the superior vena cava. It contains deoxygenated blood.

1.5.3
The chamber of the heart that contains the pacemaker (sinoatrial node) in its wall is the right atrium (labeled D).

1.5.4
The part that prevents oxygenated and deoxygenated blood from mixing is the septum.

1.5.5
The left ventricle wall is thicker than the right ventricle wall. This is significant because the left ventricle needs to pump blood with greater force and pressure to circulate it throughout the entire body, whereas the right ventricle only pumps blood to the lungs.

1.5.6
Valve E is the tricuspid valve. Its function is to prevent the backflow of blood from the right ventricle into the right atrium when the right ventricle contracts.

1.5.7
Part F is the mitral (bicuspid) valve, located between the left atrium and the left ventricle. If it is damaged and cannot open properly, the blood flow from the left atrium to the left ventricle will be restricted. This will lead to a reduced volume of blood entering the left ventricle, consequently decreasing the amount of blood pumped to the rest of the body.