Origin of life

... the primordial solar nebula. The experiment used a reducing mixture of gases ( methane , ammonia and hydrogen ). However, it should be noted that ... of earth is currently somewhat controversial. Other less reducing gases produce a lower yield and variety and the presence of free oxygen prevents ...

Diffusion

... Diffusion is the movement of matter due to the movement of the individual molecules (or atoms). Diffusion occurs in solids, in liquids, in gases and in supercritical fluids. Diffusion is caused by the thermal movement of individual molecules. Some examples of diffusion are: A balloon ...

Herpetology

... but otherwise have surprisingly little else in common. Typically, amphibians have a permeable skin that assists in the exchange of gases and respiration , have a two-chambered heart like fish, and are often bound to water for at least some part of their life, if only the laying of ...

Leaf

... side by chloroplast-containing guard cells , and two to four subsidiary cells that lack chloroplasts. The stoma complex regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Typically, the stomata are more numerous over the abaxial (lower) epidermis ...

Recombination

... and meiosis , as summarized above. In chemistry and electrical engineering , it is the state in which the hydrogen and oxygen gases form within the battery cell during charging are recombined to form water. In cosmology , the event during which electrons became bound ...

Stoma

... the same number of stomata on the two epidermis. If the plant has floating leaves, there will be no stomata on the lower epidermis as it can absorb gases directly from water through cuticle . If it is submerged leaf, no stomata will be present on both sides of it. Stoma in Greek means "mouth". ...