<span>Natural selection is when species learn to adapt to
their environment. They could (1) differential reproduction, that is, not all
organisms are able to reproduce to their fullest capacity because nature cannot
simply sustain it and (2) acquire genes, that is heredity. Certain
characteristics of organisms tend to survive if it continues to strive. If it
survives, this trait is passed down to the next generations forgetting the
other traits but only the one who could survive the environment. Therefore it
is true that <span>natural
selection is when ‘organisms inherit advantageous traits, and tend to reproduce
more successfully than other organisms’. One best example is the extinction of
other animals and some with the same species retains.</span></span>
Answer:d) contracting her pupils and increasing secretion of stress hormones.
Explanation:
Peripheral nervous system consists of 3 major neuronal levels: vegetative (reticular formation and brain stem), limbic system and neocortical level. The RAS is the link between the brain and the spinal cord.
Brain stem consists of pons, medulla oblongata and mesencephalon. Brain stem is responsible for involuntary functions such as heart beat, respiration and vasomotor activity. Limbic system represents the emotional control center. It consists of thalamus, hypothalamus and pituitary gland and maintains homeostasis. Neocortical part processes sensory information and regulates emotional responses.
Autonomic nervous system (ANS) regulates visceral activities and organs (circulation, digestion, respiration and temperature). ANS has two divisions: sympathetic and parasympathetic nervous system.Parasympathetic nervous system regulates homeostasis via the release of acetylcholine (Ach). Parasympathetic nervous system is responsible for energy conservation and relaxation.
There are three stages in the stress response: immediate effects of stress, intermediate effects of stress and prolonged effects of stress.
Answer:
Please find the detailed explanation of this statement below
Explanation:
Firstly, a repressed gene is a gene whose expression has been inhibited or repressed. The lac operon in E.coli bacteria is a regulatory unit containing structural genes, a single promoter and operator regions. The promoter is the region where the transcription enzyme (RNA polymerase) binds to in order to transcribe the genes in the lac operon. The structural genes in the lac operon can only be expressed in the presence of lactose sugar.
However, in the absence of lactose, LAC REPRESSOR, which is a transcription factor (protein), prevents the binding of RNA polymerase to the PROMOTER region by binding to the OPERATOR region of the lac operon. This inhibits the expression of the lactose genes in the operon.
Note that, the structural genes in the lac operon (lacZ, lacY, lacA) code for proteins that help break down lactose sugar for energy in the E.coli bacteria. Therefore, a bacteria cell with a repressed lac operon will be unable to degrade lactose sugar.
Yes. Half life or better known as Radioactive decay is measured in TIME. Such as seconds, minutes, hours, days, years ect...
:) hope that helps you some, best of luck!
