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:
d. xylem and phloem
Explanation: plants possess vascular bundles.these are bundles which includes xylem and phloem tissues and transport useful substances to various plant cells.
New Xylem and phloem are formed from the vascular cambium which divides into new cells .
Xylem and phloem are thin and slender with pipe-like structure.
The xylem transports water and dissolved nutrients to the cells where they are needed.
The phloem transports the product of photosynthesis (sugar) to parts what they are used up or stored .
Xylem cells are dead and consists in vessels,trachieds and xylem parenchyma.
Phloem cells are dead and consists in sieves cell, companion cells, phloem parenchyma and phloem fibres.
The answer should be coal.
Hope this helps
Answer:
d. All of these
Explanation:
Every universe has its own type of nature and the rules of that nature are totally changed from the other universe. Once the scientific ideas are verified from a number of experiment, they will not change at all and remain valid. All the natural processes which occurs is due to naturally causing agents.
