Answer: the membrane channel
Explanation:
In passive diffusion, the small water molecules can move across the phospholipid bilayer seen in blue. This layer acts as a semi-permeable or selectively permeable membrane; its hydrophilic heads are attracted to water (seen facing outwards) while its water-repellent hydrophobic tails face towards each other- allowing molecules of water to diffuse across the membrane along the concentration gradient.
Thus the water will move from an area of high concentration to an area of low concentration, until the system reaches a steady state called equilibrium- after this, there will be no net movement of water. Similarly via osmosis, the water passes through the membrane due to the difference in osmotic pressure on either side of the phospholipid bilayer this means that the water moves from regions of high osmotic pressure/concentration to regions of low pressure/ concentration to a steady state.
The dialysis tubing mimics a semi permeable membrane; it only allows water and small molecules of iodine to cross into the bag containing starch. The tubing is impermeable to starch; these large molecules require the aid of protein omplexes called membrane channels, in order to move across the membrane and against the concentration gradient.
The correct answer is option B. The scientists were studying if the mud snails can reproduce both sexually and asexually. The characteristics in the study included parameters such as the mating season, number of offspring, effect of environmental stress conditions and lack of mates. Out of all the parameters being studied can affect asexual reproduction in the mud snail but lack or presence of mates is a parameter required to be studied to determine the mode of reproduction i.e. sexual or asexual because need for mates or mate dependent reproduction occurs in case of sexual reproduction.
<span> For a start, when you have a question that needs answering in science, you formulate a null hypothesis. That is a negative statement which you then set out to prove or disprove. This is just a convention. So if your initial question is for example, "Does sugar dissolve in water?"
Your null hypothesis will be "Sugar does not dissolve in water."
You then set up your experiment and get some data.
Now if your data doesn't support your null hypothesis then you reject it and make the statement ,"Sugar does dissolve in water." As you can see from this simple example, a non-result is still a result so the idea of formulating new tests as mentioned by another answerer isn't necessary and in some ways is the incorrect thing to do. In science, hypotheses are often not supported by data and i would argue that this is the case a lot of the time. A non-result is still a result and you will have plenty to write about whichever way it goes. </span>
Greek and plomety......................
Density. Density is the measurement of how much matter is in a substance
