Option D is correct, I believe that option A is wrong because in meosis 1 sister chromatids are together option B is wrong because homologous chromosomes are in meiosis 1 not 2 option C is wrong because 4 sex cells are produced in the process of meosis 2
The contractions of the heart is what creates out blood to pulse through out body and is the basis of our blood pressure; which means this statement is TRUE.
The systolic number (top) of the blood pressure is our heart physically pushing the blood out of the heart and to the rest of the body.
The diastolic number (bottom) of the blood pressure our heart at rest when it has just finished with one pump.
The Precambrian era envelopes the major bulk of the history of the Earth, beginning from the creation of the planet approx 4.5 billion years ago and terminating with the origination of composite, multicelled forms of life approximately 4 billion years after.
The Precambrian refers to the earliest of the geologic ages that are signified by the distinct layers of sedimentary rock. The Earth was about more than six hundred million years old when life started. The planet had cooled down from its native molten state, creating a solid crust and oceans formed by water vapor in the atmosphere.
At about three billion years ago, the atmosphere of the Earth was virtually devoid of oxygen. At approximately 2.4 billion years ago, oxygen was discharged from the seas as a waste product of photosynthesis by cyanobacteria. The levels of the gas slowly raised, attaining about 1 percent around two billion years ago.
Approximately 800 million years ago, the levels of oxygen attained about 21 percent and started to breathe life into more composite species. The oxygen-rich ozone layer was also created, protecting the surface of the Earth from the harmful solar radiation.
Decomposers, as the name suggests, decompose dead plants or animals into simple compounds. They feed on dead producers from the first levels or consumers from other three levels. Breaking them down, decomposers release nutrients that producers can use.
In an ecosystem with four levels, the first level are producers, such as plants and algae. On the second trophic level, there are primary consumers, herbivores that eat plants, for example, a deer, a rabbit, a grasshopper. The next trophic level belongs to secondary consumers that eat herbivores, for example, a wolf, a fox. The highest level is tertiary consumers that eat carnivores, for example, a bear, an eagle.
The enzyme pepsin functions with a very low pH of around 2. It is found in the stomach, with the acidity coming from the hydrochloric acid present there. it breaks proteins into amino acids.
