Heterocyst-forming cyanobacteria differentiate highly specialized cells to provide fixed nitrogen to the vegetative cells in a filament. In the presence of a source of combined nitrogen such as nitrate or ammonium, Anabaena PCC 7120 grows as long filaments containing hundreds of photosynthetic vegetative cells.
Answer:
False
Explanation:
Mendel realized that the F2 had a phenotypic ratio 3:1, meaning 3/4 = 75% were yellow and 1/4 = 25% green.
Mendel observed that the F1 expressed only one of the alternative variants (in this case, only yellow seeds appeared), while the other variant (green) disappeared. Mendel named dominant the expressed variant. Mendel allowed auto pollination and observed that in the second generation, F2, the other disappeared variant reappeared. Both alternative variants were present in the F2. Mendel named recessive the second alternative variant.
Mendel thought that hereditary traits determined by discrete factors were the possible explication for these phenotypes. These factors should have been present in the F1 in pairs. One of them came from one parental plant, and the other factor came from the other plant. These factors then separated again when sex cells were produced, giving two types of gametes, each with only one factor.
Mendel concluded that each individual (plant) has a pair of factors (alleles), one for each trait (yellow and green) and that the pair separates (segregates) during the formation of the gametes. This conclusion is known as the segregation principle (First Mendels´ Low).
The techniques earthquake is a term which refers to the science of constructing buildings that are able to withstand the effects of an earthquake.
The instruments used to measure the intensity and direction of an earthquake are known as a seismograph and a seismoscope. The seismograph measures the movement of the ground during an earthquake. The seismoscope shows the direction of an earthquake.
The Intensity Scale is a scale that measures the intensity of an earthquake. It also measures the effects of an earthquake.
Pollution plays a huge factor. With factories in demand, more and more substances are being released into Earth's atmosphere, resulting in higher temperatures.
The answer is greenhouse gases
