The amount of energy at each trophic level decreases as it moves through an ecosystem. As little as 10 percent of the energy at any trophic level is transferred to the next level; the rest is lost largely through metabolic processes as heat.
B. the addition of one phosphate group
Answer:
Diffusion
Explanation:
Diffusion is a process of passive transport in which molecules move from an area of higher concentration to one of lower concentration.
Transcriptional activator proteins may control the level of transcription of eukaryotic genes by bind to promoters that enhance or regulate the transcription.
Repressors may control the level of transcription of eukaryotic genes by binding to DNA sequences that work either as silencers or promoters in order to inhibit the transcription impeding the access to where the transcriptional activator proteins may bind.