The proposal is made that seed scientists need an internationally acceptable hierarchical system of classification for seed dormancy. Further, we suggest that a modified version of the scheme of the Russian seed physiologist Marianna G. Nikolaeva be adopted. The modified system includes three hierarchical layers – class, level and type; thus, a class may contain levels and types, and a level may contain only types. The system includes five classes of dormancy: physiological dormancy (PD), morphological dormancy (MD), morphophysiological dormancy (MPD), physical dormancy (PY) and combinational dormancy (PY + PD). The most extensive classification schemes are for PD, which contains three levels and five types (in the non-deep level), and MPD, which contains eight levels but no types. PY is not subdivided at all but probably should be, for reasons given. Justifications are presented for not including mechanical dormancy or chemical dormancy in the modified scheme. PD (non-deep level) is the most common kind of dormancy, and occurs in gymnosperms (Coniferales, Gnetales) and in all major clades of angiosperms. Since, first, this is the class and level of dormancy in seeds of wild populations of Arabidopsis thaliana and, secondly, Type 1 (to which seeds of A. thaliana belong) is also common, and geographically and phylogenetically widespread, it seems that biochemical, molecular and genetic studies on seed dormancy in this model species might have rather broad application in explaining the basic mechanism(s) of physiological dormancy in seeds.
Biology is the study of life so a Biologist would study biology: the study of life and living things.
Answer:
during the process of photosynthesis, cells use carbon dioxide and energy from the sun to make sugar moleculezs and oxygen..... then, via respiration processes, cells use oxygen and glucose to synthesize energy- rich carier molecules such as ATP, and carbon dioxide is produced as a waste product.
Explanation:
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Answer:
Species 1(A): D F H I K
Species 2(B): L E
Species 3(C): G J
Explanation: the biological species concept defines a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring. This means that all members of these populations (called conspecifics) can contribute to a common gene pool. Conspecifics are organisms or populations that belong to the same species. Genes are transferred between conspecific populations through both direct and indirect gene flow.
The main function of cladodes is : Photosynthesis
Cladodes are a type of modified stems that has a flattened form like leaf. The function is actually also to replace the leaves in photosynthesis process. Hope this helps