Natural selection affects allele frequency. If an allele confers a phenotype that enables an individual to better survive or have more offspring, the frequency of that allele will increase.
The type of contraception that works because ovulation is prevented is the birth control pills. Ovulation is when the egg that has left from the ovaries and moved into Fallopian tube, that lastly moves into the uterus, which is the women,s most fertile time of the month when the egg is in the uterus it waits to be fertilized, and when it is not fertilized it is released which leads to periods. Ovulation occurs 14 days after the first day of the menstrual cycle.
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.
