D. descriptive investigations
Explanation:
A scientist studying the star Alpha Centauri would probably rely on descriptive investigation to gather data.
In descriptive investigation, experiments cannot be performed since the subjects cannot easily be manipulated or they are far too inaccessible. This form of investigation is based on indirect qualitative investigation of a phenomenon.
- Alpha Centauri is a distant star several light years away from the vicinity of the scientist.
- The best way to investigate this distance body is to make inferences from the evidence gathered from observatory stations using telescopes.
- Astronomers can collect different information and give vivid description of the distant start.
- It is highly impossible to make comparisons and alter variable in this kind of investigation.
learn more:
experiment brainly.com/question/5096428
#learnwithBrainly
T cell receptor, Cytotoxic T Cell, CD4, Antigen, Bacterium,
B – cell, Cell mediated response, Class II MHC, Cytokines, and Humoral Response
are the components for the activation of a helper t cell by a dendritic cell.
The energy before and after a process must be the same.
Answer:
Depending on the stimulus, graded potentials can be depolarizing or hyperpolarizing. Action potentials always lead to depolarization of membrane and reversal of the membrane potential. Amplitude is proportional to the strength of the stimulus. ... Duration of graded potentials may be a few milliseconds to seconds.
Explanation:
Answer:
Radiometric dating methods
Explanation:
Absolute dating is the process of determining an age on a chronological or specified time scale in which events occurred in archaeology and geology. Absolute dating can be determined by using properties of the atoms that make up materials.
The most common method of absolute dating uses by geologists is radiometric dating methods which is based on the natural radioactive decay of certain elements such as potassium and carbon found in the rocks. By comparing the ratio of parent isotope with a known half-life to daughter product in the rock, the age of the rock can be determined.
The carbon-14 isotope is used in radiocarbon dating, but is only useful for measuring recently formed rocks in the geologic past. The decay of Potassium-40 isotope known as potassium-argon (K-Ar) method allows dating of materials that up to 1,000 billion years old.
