<span>There are many indicators for predator presence. Some of them are:
Being able to spot predator marks like scratches or fur.
Being able to feel predator movements.
</span><span>Echo-location </span>For example, moths respond to the echo-location calls from their bat predators; moths drop to the ground once they hear the sound pulse from the bat.
Answer: tympanic membrane
<em>Homo sapien ((human))</em>
<em>Bat ((mammal))</em>
<em>aliigator ((reptilious))</em>
<em>Frog ((amphibious))</em>
<em />Fish
<span>A. the same DNA molecule is expressed differently.</span>
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.