The Chinese. All other cultures most like did not support astronomy.
Vestigial traits are adaptations to environmental pressures which are no longer present.
homologous structures are similar structures found in different species that were present in a common ancestor.
analogous traits are similar traits found in different species that were developed independently (this process is known as convergent evolution)
The brain stem is the answer that you are looking for
Answer:
Here are the answers:
a. 4 Cell determination as an issue in the *rest is missing*
b. 4 They assumed that different ways of separating an embryo into two parts would be equivalent as far as the fate of the two parts was concerned.
c. 4 I and III only
Explanation:
The passage demonstrates the importance of two factors in the development of an embryo: cleavage planes of division of embryonic cells and cell differentiation.
Cleavage Planes:
Cleavage basically refers to the division of the zygote into a large number of cells called blastomeres. Cleavage planes are geometrical lines or orientations along which cleavage takes place. Since, all embryonic cells are the precursors of some type of body cells, the cleavage planes determine if the cells are adequate for growth and development.
Cell Differentiation:
Cell differentiation is the transition of an undifferentiated cell into a specialized one. For example, stem cells are undifferentiated cells that develop into progenitor cells that mature into a specific cell lineage. For an embryo to regenerate, the presence of adequate embryonic stem cells is crucial. Embryonic stem cells are present in abundance before the gastrulation phase of embryonic development, after which they rapidly start differentiating.
The purpose of the brain's gyri and sulci, or ridges and grooves, is to increase surface area.
<h3>What is the name for the raised ridges in the cerebrum?</h3>
The shallow grooves on the cerebral cortex's surface are referred to as sulci, while the higher tissue ridges are called gyri.
Signals are transferred between nerve cells in different regions of the brain and body through white nerve fibres that are below the skin. The neocortex, a six-layered structure present in animals, has a wrinkled surface that enhances its surface area.
The cerebellum has an odd surface appearance that hides the fact that the cerebellar cortex, a layer of grey matter, makes up the majority of the structure. This layer's ridges are collectively referred to as folium.
learn more about cerebrum refer
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