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An endosperm is formed after the two sperm nuclei inside a pollen grain reach the interior of a female gametophyte or megagametophyte, also called the embryonic sac.One sperm nucleus fertilizes the egg cell, forming a zygote, while the other sperm nucleus usually fuses with the binucleate central cell, forming a primary endosperm cell (its nucleus is often called the triple fusion nucleus).
"The ground tissue of plants includes all tissues that are neither dermal nor vascular. It can be divided into three types based on the nature of the cell walls. This tissue system is present between the dermal tissue and forms the main bulk of the plant body. Parenchyma cells have thin primary walls and usually remain alive after they become ...
The hair follicle is an organ found in mammalian skin. [1] It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between hormones, neuropeptides, and immune cells. [1]
Humans in all civilizations are social animals and use their language skills and tool making skills to communicate. These communication skills enable civilizations to grow and allow for the production of art, literature and music, and for the development of technology. All of these are wholly dependent on the human biological specialisms.
It is commonly stated that hair grows about 1 cm per month on average; however reality is more complex, since not all hair grows at once. Scalp hair was reported to grow between 0.6 cm and 3.36 cm per month. The growth rate of scalp hair somewhat depends on age (hair tends to grow more slowly with age), sex, and ethnicity. [3] Thicker hair (>60 ...
Environmental effects on human physiology are numerous; one of the most carefully studied effects is the alterations in thermoregulation in the body due to outside stresses. This is necessary because in order for enzymes to function, blood to flow, and for various body organs to operate, temperature must remain at consistent, balanced levels.
In fact, a protein found in human hair called L-cysteine is sometimes used as an additive to certain foods. L-cysteine is an amino acid found in keratin, which some food manufacturers use to ...
Mesenchyme is characterized morphologically by a prominent ground substance matrix containing a loose aggregate of reticular fibers and unspecialized mesenchymal stem cells. [5] Mesenchymal cells can migrate easily (in contrast to epithelial cells , which lack mobility, are organized into closely adherent sheets, and are polarized in an apical ...