Answer:
The correct statement concerning the cell membrane lipid molecules is that "energy is not expended during diffusion" (Option d)
Explanation:
Biological membranes are formed by two lipidic layers arranged with their hydrophilic polar heads facing the exterior and the interior of the cells, and their hydrophobic tails against each other. Membranes are fluid, which means that molecules that form it have the capability to move through it.
Lipids can easily change places with other neighbor lipids by <u>lateral diffusion</u> in the same layer. This is passive diffusion, which means that it does not need energy to happen.
Lipids can also diffuse transversally to the other layer, but this kind of movement is not as easy as lateral diffusion.
There are also other lipidic movements as rotational diffusion that imply the rotation of the molecule.
Through this lipidic bilayer, there is also a passive transport of some particles from one side of the cell to the other which happens because of concentration differences.
Answer:
Explanation:
We recognize that total occurrence equals new cases of disease over time divided by the number of people at risk at the onset.
Mathematically:
Given that:
Number of the population at risk = 1000 individuals
New cases during Jan 1 - Dec 31 = 60 because;
At 20 occurred on June 30 & 40 on Sept. 30) & no new cases were identified after that:
∴
Answer: Option C
6CO2 + 12H2O + light --> C6H12O6 + 6O2 + 6H2O
Explanation:
Photosynthesis is the process by which autotrophs such as green plants generate their food (usually sugar molecules) from simple inorganic molecules like atmospheric carbon dioxide and water, in the presence of sunlight trapped by chlorophyll.
From the equation of photosynthesis,
- several units of glucose molecules (C6H12O6) is produced and then stored in plants tissues as starch.
- Oxygen is released as by-product
- Some water is given off also
<h3><u>Answer;</u></h3>
d. before the Neogene era.
<h3><u>Explanation;</u></h3>
- <em><u>The Silurian Period was a third period of the Paleozoic Era that occurred from 443 million to 416 million years ago. This period occurred after the Ordovician Period and was then followed by the Devonian Period.</u></em>
- Silurian period is the period that many biologically significant events took place. There was a widespread radiations of crinoids, continued priliferation and expansion of the brachiopods and also the oldest known fossils of coral reefs.
The answer is terracing.
Terracing is a type of landscaping characteristic for steep slopes and mountains. Graduated terraces are used to farm on this kind of terrain to reduce erosion. This way crops are planted on graduated level areas and not on steep terrain, and risk of surface runoff is reduced.
