Oil-immersion objectives are limited to use with coverslip-prepared samples, since they don't have enough working distance to focus through the 1 mm or thicker plastic wall of a typical cell culture vessel.
The embryonic stage lasts approximately 4 week(s), beginning at conception. Details about stages of development can be found below.
<h3>What are the stages of development?</h3>
The stages of development of a human is summarized into four stages as follows:
- Embryonic stage
- Germinal stage
- Fetal stage
In the embryonic stage of development, which occurs after conception, the baby is called an embryo. Embryonic stage lasts 4 weeks.
During the embryonic stage, the cells of the embryo (called embryonic stem cells) multiply and develop. They become the hundreds of different types of cells needed to make a whole human body.
Learn more about embryonic stage at: brainly.com/question/14233911
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Answer:
The numbers after the arrows represent the number of the questions that should be considered next.
Explanation:
In the dichotomous key, the characteristics of the fish that will be considered must be carefully observed in order to develop a two-option system. Taking into account the fish features, the dilemmas generated will carry the number 1 (1a or 1b). Each option will present a description of the organism, and at the end of that choice there will be another number (arrow plus number), which belongs to the next feature described or questions asked about the organism to take into account to identify the taxonomic group. Depending on the option chosen, that question will lead to another question to be answered.
The Precambrian is the earliest era. It is followed by the Paleozoic, when multi-cellular life first flourished on earth After that came the Mesozoic - 'middle life' - the era before the current one which is the Cenozoic. Note that the Paleozoic, Mesozoic and Cenozoic are all part of the Phanerozoic Eon.
Biogentically developed GMO foods are modified with certain/chemical.