D) laboratory experiments because every experiment needs a control and a variable.
Answer:
The correct answer would be a lipid-soluble signal.
Signal transduction refers to the set or cascade of bio-chemical reactions take place in a cell in order to transmit the chemical or physical signal from outside the cell to inside target molecule.
It is usually initiated by receptors present on the membrane of the cell which sense the extracellular stimulus (such as ligand, hormone, pressure, temperature, pressure etc). Once activated, these receptors activate the cascade of reaction which ultimately reaches the target molecule and produces a cell's response.
In contrast, the lipid-soluble signals (such as steroidal hormones, thyroid hormone etc) enter the cell membrane without any hindrance. They directly bind to intra-cellular receptor present in the cytoplasm or on the nuclear membrane.
The hormone-receptor complex then enters the nucleus and act as transcription factor and produces the response in the form of transcription.
Homologous chromosomes separate but sister chromatids remain joined at their centromeres. Meiosis results in genetic variation among its product cells. ... -Genetic material is exchanged between homologous chromosomes in meiosis during crossing over.
Answer:
the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.