Human skin colour is primarily due to the presence of melanin in the skin. Skin colour ranges from almost black to white with a pinkish tinge due to blood vessels underneath. In animals melanin pigments are derivatives of the amino acid tyro sine.

Correct Option: A

Human skin colour is primarily due to the presence of melanin in the skin. Skin colour ranges from almost black to white with a pinkish tinge due to blood vessels underneath. In animals melanin pigments are derivatives of the amino acid tyro sine.

A typical adult human skeleton consists of 206 bones. Individuals may have more or fewer bones than this owing to anatomical variations

Correct Option: E

A typical adult human skeleton consists of 206 bones. Individuals may have more or fewer bones than this owing to anatomical variations

Blood is considered a connective tissue for two basic reasons:
(1) it has the same origin as do the other connective tissue types and
(2) blood connects the body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing the wastes. In circulating blood two different cell types are found: enucleated erythrocytes or red blood cells and nucleated leukocytes or white blood cells.

Correct Option: B

Blood is considered a connective tissue for two basic reasons:
(1) it has the same origin as do the other connective tissue types and
(2) blood connects the body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing the wastes. In circulating blood two different cell types are found: enucleated erythrocytes or red blood cells and nucleated leukocytes or white blood cells.

The pericardium is a double-walled sac containing the heart and the roots of the great vessels. It is a tough double layered membrane which covers the heart. The space between the two layers of it is filled with a pericardium fluid which protects the heart from any kind of external jerk or shock.

Correct Option: A

The pericardium is a double-walled sac containing the heart and the roots of the great vessels. It is a tough double layered membrane which covers the heart. The space between the two layers of it is filled with a pericardium fluid which protects the heart from any kind of external jerk or shock.

In photosynthesis, carbon dioxide is converted into sugars in a process called carbon fixation. Carbon fixation is a redox reaction, so photosynthesis needs to supply both a source of energy to drive this process, and the electrons needed to convert carbon dioxide into a carbohydrate, which is a reduction reaction. The general equation for photosynthesis is therefore: Carbon dioxide + electron donor + light energy → carbohydrate + oxidized electron donor.

Correct Option: B

In photosynthesis, carbon dioxide is converted into sugars in a process called carbon fixation. Carbon fixation is a redox reaction, so photosynthesis needs to supply both a source of energy to drive this process, and the electrons needed to convert carbon dioxide into a carbohydrate, which is a reduction reaction. The general equation for photosynthesis is therefore: Carbon dioxide + electron donor + light energy → carbohydrate + oxidized electron donor.