Answer:
A) stratum basale.
Explanation:
The epidermal layer consists of five layers. This is not having any blood vessels and known as avascular. The four-layer starting from stratum basale to stratum corneum is referred to as thin skin. But the skins of foot and palm has another layer called stratum lucidum. This layer forms the five layers of the epidermis.
The stratum basale is the deep layer of the epidermis. Below this layer dermis is present. This layer consists of basal cells which are precursors of keratinocyte cells. The stratum basale is a single layer cell and it undergoes continual mitosis. So that this cell produces new cells and these new cells replace the other older cells above it.
As the basal cells are precursors of keratinocytes, they produce all keratinocytes of the epidermis.
Two other types of cells are produced from this layer - Merkel cell, and melanocyte. Merkel cells act as touch receptors and melanocytes produce melanin pigments.
Euthrophication is caused by excess nutrient run off, such as nitrogen or phosphorus. A common chemical that generally cause euthrophication is fertilizers from farm, if there's heavy rainfall or floods, they're easily washed into the rivers and lakes to cause euthrophication.
Euthrophication generally cause a sudden large scale algao bloom, or other plants, and they may cover the whole surface of water. Once these plants die, decomposers such as bacteria decompose them and take in oxygen for respiration, such that animals from the river originally may die due to lack of oxygen.
Answer:
The history of Earth covers approximately 4 billion years (4,567,000,000 years), from Earth's formation out of the solar nebula to the present. Earth formed as part of the birth of the solar system: what eventually became the solar system initially existed as a large, rotating cloud of dust and gas.
Explanation:
A combination of a dominant and recessive allele (ex: Hh)
