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.
Answer:
DNA
proteins
genes
chromatin
chromosomes
chromosome
Explanation:
The “code” for physical traits is found in a molecule called DNA. Segments of this molecule that code for specific proteins are called genes. In order to conserve space and protect the molecule, DNA wraps around proteins to form chromatin. When a cell is about to divide, DNA wraps up even tighter into chromosomes. Complex organisms have many molecules of DNA in every cell, and each molecule is commonly referred to as a chromosome, even if it is not wrapped up as one.
Answer:
I believe it is to partition the habitat between the young and the adults.
Explanation:
