### physical process | biological process:

Senescence
* brings both the fall colors and leads to renewed spring growth.
* is an active and passive cessation of growth
  - inevitable consequence of wear and tear
  - different than aging
  - regarded as a non-adaptive phenomenon
* is the dropping of leaves, flowers, fruits, or other plant parts
  - phase of plant growth after full maturity that results in tissue death
  - term used to describe the aging and death of a tree or a part of it
  - triggered by progressive reduction in telomere length during DNA replication
  - universal, intrinsic, progressive, and deleterious
* natural part of the life cycle of plants.
* physiological decline intrinsically related to the age of the tree.
* starts together with flower development.
* term used to indicate gradual deterioration of the body with age.
* typically occurs in fall when moisture becomes limiting and plants are exposed to frost.

### physical process | biological process:

Synapsis
* Most synapses develop on thorn like processes of dendrites, the dendritic spines
  - have a macular shape
* Synapses allow cells to talk and listen to one another
  - are also the site of action of many mind altering drugs
* Synapses are connections between cells that make the nervous system function
  - that transmit information between nerve cells and their targets
  - critical for relaying nerve impulses
  - highly active biochemical sites, requiring a great deal of protein for their function
  - one wiring system meeting another
  - polarized, i.e., the impulses pass in one direction only
  - responsible for much of the brain's activity
  - sites of where neurotransmission and trophic factor signaling occurs
  - specialized functional cell junctions to propogate cellular signals
  - strongest when the learning has a function
  - structures that permit communication between neuronal cells
* Synapses are the connections between nerve cells that mediate information transfer in the brain
  - nerves
  - neurons, or nerve cells
  - contact points where one neuron communicates with another
  - gaps between adjacent neurons
  - junction points between neurons
* Synapses are the key functional elements of the brain
  - structures for information processing in the brain
  - major points at which information is transmitted between neurons in the brain
  - primary points of communication between cells of the nervous system
  - telephone lines that enable brain cells to communicate
  - therefore capable of linearly transmitting presynaptic release
  - very small gaps between neurons
  - become bigger by recruiting more constituent molecules
  - bring signal values to the input of the neuron
* Synapses can also occur between neurons
  - be excitatory or inhibitory
* Synapses can be preset to fire at specified times or to fire stochastically
  - differ in the effect that they have on the output of the neuron
  - exhibit different forms of plasticity over a wide range of time scales
  - grass-roots, interfaith, international, peace action network
  - have a large lipid component
  - modify slowly relative to characteristic neuron response times
* Synapses occur at the end of the body's nerve terminals
  - exclusively at varicosities on corticostriatal axons
  - typically occur between an axon and a dendrite , though many other arrangements also occur
* allows crossing over between homologous chromosomes.
* are convergence
  - situations
* consists of the pairing of homologous chromosomes.
* is the process of linking of the replicated homologous chromosomes.