Answer:
B) cytoplasmic streaming in hyphae
Explanation:
Fungal mycelium refers to the branched vegetative structure of the fungi which is formed by the growth of the hyphae. The hyphae contain three zones of growth: the apical, subapical and zone of vacuolation.
The hyphae grow in the apical region which forms a branched structure in which the cytoplasm continuously moves between the hyphae at the point of fusion towards the growing tip. This movement of the cytoplasm towards the growing tip is known as "cytoplasmic streaming".
This streaming of cytoplasm is responsible for the formation of a zone of vacuolation and the mycelium is formed.
Thus, Option-B is the correct answer.
The growing tip eventually gives rise to a branch. This is the beginning of the branched mycelium. Growing tips that come in contact with neighbouring hyphae often fuse with them to form a hyphal net. In such a vigorously growing system, the cytoplasm is in constant motion, streaming toward the growing tips. Eventually, the older hyphae become highly vacuolated and may be stripped of most of their cytoplasm.
1. Eukrayotes cells contain membrane-bound organelles, such as the nucleus, while prokaryotes cells do not.
2. Eukaryotes are often multicellular whilst prokaryotes are unicellular. Although there are some exceptions –unicellular eukaryotes include amoebas, paramecium, yeast.
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Answer:
There are four principles at work in evolution—variation, inheritance, selection and time. These are considered the components of the evolutionary mechanism of natural selection.
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The outer core<span> of the Earth is a fluid layer about 2,300 km thick and composed of mostly iron and nickel. It that lies above Earth's solid inner </span>core<span> and below its mantle. </span>
Answer:
The animals present body structure is due to evolution. It is seen in each part including the structure of the heart. The vertebrate heart becomes complex from a simpler form.
Invertebrates, the heart of fishes is two-chambered having one auricle and one ventricle. The deoxygenated blood gets purified in the gills. They are aquatic and no lungs for breathing. The hearts pump a mixture of oxygenated and deoxygenated blood to the body.
The amphibians and reptiles have 3 chambered heart as they lead terrestrial mode of life. The gills modified into the lungs. The left auricle receives pure blood and the right auricle receives deoxygenated blood. The blood purified in the lungs and in the ventricle, both types of blood get a mix. The ventricle pumps the mixed-blood throughout the body.
In the case of birds and mammal, the heart is 4 chambered and the oxygenated and deoxygenated blood are separated. These two are higher vertebrates. No mix of pure and impure blood, the body receives only the oxygenated blood.
This shows to construct the phylogenetic tree of vertebrates - the fishes should be in the bottom, and above it amphibians, reptiles, then, mammals and birds on the top branch of the tree. As the chambers and structure of the hearts modified one after another.
