The survivorship of gobies, and the fecundity of sparrows, both decline at high population densities. This is an example which phenomenon?
a) density dependence
b) survival of the fittest
c) density independence
d) degenerate evolution

a) Density dependance

Explanation:

Density dependant factors are those factors that influence a population differently if the population is crowded than if it is not crowded.

For example :

These factors include :

Hence according to the given scenario, the survivorship of gobies and the fecundity of sparrows, both decline at  high population densities , so this phenomena is density dependance.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

about 40,000,000 results (0.81 seconds)  

search results

what do the different brain waves do?

explanation:

brainwaves are produced by synchronised electrical pulses from masses of neurons communicating with each other. brainwaves are detected using sensors placed on the scalp. brainwave speed is measured in hertz (cycles per second) and they are divided into bands delineating slow, moderate, and fast waves.