PHP â Sort Functions For Arrays. In this chapter, we will go through the following PHP array sort functions: sort() â sort arrays in ascending order. rsort() â sort arrays in descending order. asort() â sort associative arrays in ascending order, according to the value.
Environmental factors that can affect gene expression. Exposing a fetus, infant, or child to a chemical or nutritional (or other) stressor during development can affect the risk of disease development even into adulthood. The mechanisms involved are probably epigenetics (Boekelheide et al. 2012).
The presence of drugs or chemicals in an organism's environment can also influence gene expression in the organism. Cyclops fish are a dramatic example of the way in which an environmental chemical can affect development.