unique propertys of water how is this property explained by the structure of water molecules and the bonds between them

Describe five factors that influence the value of fuel

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

Which best describes a gene? a. a sister chromatid b. a chromosome c. a tetrad d. a piece of a chromosome