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.
I would go with the last one, allowed scientists to better identify the location of fossils and change prior scientific knowledge
The major muscles involved while performing a wall sit or squat are the quadriceps muscles.
Explanation:
Exercises like wall sit or squat are an isometric exercises which works the entire group of lower body muscles.
Isometric exercises are endurance building exercises which improves the muscle endurance by holding it in a position for longer time. These exercises does not involve any big bodily movements but works by tensing the muscles.
Both these exercises primarily involve the front thigh muscles or the quadriceps. Squats and wall sits help to tone and shape the quads and other muscles involved. The angle of the body should be maintained at right angle to reduce the pressure on these muscles.
Other muscles which are involved in these exercises are the hamstrings, core, lower back muscles etc.
Answer:
Small and lipid soluble cortisol can pass through nonpolar core of the plasma membrane.
Explanation:
Cortisol is a lipid-soluble steroid hormone with a compact structure. The plasma membrane is a bilayer of phospholipids.
The phospholipids are amphipathic molecules with a polar head and nonpolar tails. The nonpolar tails of the two layers of phospholipids are packed away from the watery medium and make the core of the plasma membrane.
Being a lipid-soluble hormone with a small structure, cortisol can pass through the nonpolar core of the plasma membrane easily to activate its receptors and alter the gene expression.
<h2>Kinase cascade </h2>
Explanation:
Normally, PK2 activates PK1
- PK1 and PK2 normally work sequentially in an intracellular signaling pathway
- If PK1 is permanently activated, a response is seen independently of whether or not PK2 is present
- If PK1 activated PK2, no response should be seen if PK1 were activated in the absence of PK2
- PK2 normally needs to activate PK1 for the cells to respond to the signal
- When PK2 is permanently activated in the absence of PK1, PK1 is not there to relay the signal
