Answer:
The correct answer is A. a rotating cloud of dust and gas.
Explanation:
Nebulae are regions of the interstellar medium (clouds) made up of gases (mainly hydrogen and helium) and dust. In other words, nebulae are concentrations of gas in which we find hydrogen, helium and stardust in greater quantities. They are structures that are actually very important for the universe, this because inside it is the place where stars are born, which arise due to the condensation and aggregation of matter. The nebular theory states that the Solar System reached the form current from a solar nebula (a gas cloud), more than 4.5 billion years ago. The large cloud of molecular gas was affected by a certain phenomenon that would have taken place in the vicinity. Like the explosion of a supernova or the passage of a star that would produce a strong gravitational impact. The result of this event made the matter agglomerate in different places. The high concentration of matter caused the nebula to collapse. Becoming a protostar, (bodies whose characteristic is to be surrounded by clouds and contain preplanetary matter inside), that is, gaseous matter in the outermost part and solid inward. At the core of this structure, the temperature is so dominant that nuclear reactions take place to compensate for the gravitational force. This leads to a hydrostatic equilibrium and the formation of a fundamental star: the Sun. The rest of the mass flattened, forming a protoplanetary disk where the protoplanets were being formed, which would evolve to become the current planets, their satellites and the others bodies of the solar system.
They build up Muscle Tissue :)
It does not include a gas phase; although small amounts of phosphoric acid (H3PO4) may make their way into the atmosphere, contributing—in some cases—to acid rain
The labeled anatomical features of the muscle filament are attached as an image.
Muscle filament or Myofilaments are the two protein filaments of myofibrils in muscle cells. The two proteins are myosin and actin and are the contractile proteins involved in muscle contraction.
- It has two filaments, a thick one made up mostly of myosin, and a thin one composed mostly of actin
- Actin is a filament made up of protein that contributes to the contractile property of muscle. It is found in two forms, G-actin (monomeric globular actin) and F-actin (polymeric fibrous actin)
- Tropomyosins are contractile proteins that regulate contraction in both muscle and non-muscle cells with help of myosin and actin filaments. It is present in animal cells.
- A troponin complex is a group of three proteins, troponin T, troponin I, and troponin C, subunits located on the thin filament of the contractile apparatus.
Thus, the correct labeled anatomical features of the muscle filament is attached as an image.
Learn more about Actin and myosin:
brainly.com/question/13989896
I believe (not sure) that the answer is B, viruses must invade their host before being able to reproduce.
I remember seeing a diagram of the general life of a virus, and I remember seeing the virus sticking to a cell, merging in, and reproducing thereafter (sort of like a factory). Once again, I am not sure and the answer may as well be another one.
