Questions

Candidate Key – A Candidate Key can be any column or a combination of columns that can qualify as unique key in database. There can be multiple Candidate Keys in one table. Each Candidate Key can qualify as Primary Key. 

Primary Key – A Primary Key is a column or a combination of columns that uniquely identify a record. Only one Candidate Key can be Primary Key.

• One needs to be very careful in selecting the Primary Key as an incorrect selection can adversely impact the database architect and future normalization. For a Candidate Key to qualify as a Primary Key, it should be Non-NULL and unique in any domain.

The U.S. Army identifies eight core leadership competencies. One of these--leading by example--exemplifies the warrior ethos. The leader is always required to behave in a way that provides those under his or her command with a positive and effective role model.

The warrior ethos is a value that is eschewed by the U.S. Army.

The Army defines it as the adherence to a code that includes always putting the mission first, never accepting defeat, never quitting, and never leaving behind a comrade who has fallen.

An organelle called Eyespot allows some protists to detect light. It allows the cells to sense light direction and intensity and respond to it by swimming either towards the light (positive phototaxis) or away from the light (negative phototaxis).

Eyespot is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids.

Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis. Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red pigment granules.

Goa

Protoplasm is the living content of a cell that is surrounded by a plasma membrane.

J. E. Purkinje in the year 1839 coined the term 'protoplasm' for the fluid substance of the cell.

The red blood corpuscles  or erythrocytes usually carry antigens and there are two types of antigens. The A group persons have antigen A in their red corpuscles and the B group have antigen B in their red corpuscles. The AB group person have both antigen A and antigen B in their erythrocytes. The 'O' group persons have no antigens in their red corpuscles.