A. Natural Selection. This is because the weeds that are not resistant to it die out before they can reproduce, but the resistant ones grow to maturity and then reproduce, passing down the resistance gene. Over time, the resistance gene would become a normal thing in weeds, while the non-resistant gene would not exist anyone, since the gene could not be passed on.
* More than 40 proteins and glycoproteins involved in the complement system are synthesized by the liver, macrophages, epithelial cells, they are present in the blood in plasmatic form, membrane, some have an enzymatic activity, regulator or membrane receptorThese are elements of the humoral innate immune response, they fight infections, purify immune complexes and apoptotic bodies.
<span>There are indeed three ways to activate the complement:</span>
Classical pathway: Activated by Immunoglobulins in immune complexes, aggregated Immunoglobulins, DNA, CRP, apoptotic bodies .......it involves nine fractions, starting with C1, then C4, C2, C3, to form a classical C5 convertase, then, activation of C5, C6, C7, C8, C9.
Alternative pathway: activated by polysaccharides (bacterial endotoxin), vascular wall poor in sialic acid, aggregated IgE ...C3b like is the first component in the alternate channel cascade, it will create an amplification loop, and form an alternative C5 convertase.
Lecithin pathway: Activated by mannose, fucose (carbohydrate of microorganisms)The first component is the complex MBL / MASP1 / MASP2: "mannose-binding protein": works according to the same principle as the complex C1 of the classical way (MASP2 cleaves the C4 and the rest of the cascade is equivalent to that of the classical way).
the three ways have the same outcome: A C5 convertase (formed by one of the pathways) cleaves C5 into C5a and C5b: C5b is deposited far from other fractions on the antigenic surface. The fixation of C5b in the cell is followed by that of C6, C7, C8, and C9 (9 molecules of C9): formation of the membrane attack complex (MAC) ==> Death of the cell by osmotic shock
There are more than 5 factors, but here are perhaps the most important ones:
1) Light: Light energy is a crucial component in photosynthesis, as it is the primary energy source of the process.
2) Carbon Dioxide: Another key ingredient in photosynthesis.
3) Temperature: There is an optimum temperature for photosynthesis that varies from organism to organism. Too cold or two hot, and rate of photosynthesis will be lower.
4) Water - Like almost all life process, water is a key component in photosynthesis.
5) Oxygen. A common misconception is that plants only "breathe in" carbon dioxide and expel oxygen. Plant cells actually require oxygen as well in order to function, and thus oxygen is a necessary part of photosynthesis.
D. A small male will do better mating at sea when suitable beaches are more common than are large, dominant males.
When small males are relatively abundant then would a male be expected to improve his fitness by attempting to mate at sea rather than establishing a harem.
The ability of an organism to reach reproductive age, find a mate, and give birth is referred to as biological fitness, sometimes known as Darwinian fitness. In essence, the number of offspring an organism has over the course of its lifespan determines its biological fitness.
Harem- A group of animals known as a harem consists of one or more males, several females, and the offspring of those females. The dominant male drives away other men and maintains the group together.
The given question is incomplete, the complete question is,
Q. When would a make be expected to improve his fitness by attempting to mate at sea rather than establishing a harem.?
A. A large, competitively dominant male will do better matting at sea when small males are relatively abundant.
B. A large, competitively dominant male will do better matting at sea when suitable beaches are more common than are large, dominant males.
C. A small male will do better mating at sea when suitable beaches are rare and successfully defended by large males.
D. A small male will do better mating at sea when suitable beaches are more common than are large, dominant males.
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