Which are the special proteins in muscles that contract and relax to cause movement?

 

Hemopoiesis begins in the red bone marrow, with hemopoietic stem cells that differentiate into myeloid and lymphoid lineages.

Myeloid stem cells give rise to all the other formed elements, including the erythrocytes; megakaryocytes that produce platelets; and a myeloblast lineage that gives rise to monocytes and three forms of granular leukocytes: neutrophils, eosinophils, and basophils.

A cytoskeleton is the frame that gives shape to a cell. And also it offers support, and facilitates movement through three main components:

microfilaments,

intermediate filaments, and

microtubules.

The cytoskeleton helps the cell move in its environment and controls the movement of all of the cell's interior workings.

Heritable variation is one of the four most important factors that affect whether natural selection can occur. These factors include

1) Heritable variation

2) Descent with modification

3) Struggle for survival, and necessarily if the others are satisfied

4) Survival of the fittest.

Heritable variation allows for possibly beneficial, negative, or even neutral mutations to get filtered during each generation by natural selection--weeding out negative mutations, passing on positive and neutral ones. Without heritable variation, species would quickly fall victim to parasites who take advantage of identical genetic material in a population and evolution would not occur.

Variation is the raw material of evolution.

The rungs or the sides of the DNA ladder is made of Deoxyribose, which is a pentose, and a phosphate group are the two molecules together form the two sides of the DNA i.e, A sugar (deoxyribose) and a phosphate.

Axons make up a majority of the matter in a nerve is the one statement regarding nerves is incorrect.

All living cells arise from pre-existing cells is one component of the cell theory.

The Cell Theory is one of the basic principles of biology.

The Cell Theory states:

1. All living organisms are composed of cells. They may be unicellular or multicellular.

2. The cell is the basic unit of life.

3. Cells arise from pre-existing cells.

From the aboe given options, only extreme and unexplained tiredness is the symptom of AIDS.

The other symptoms of AIDS include: recurring fever, thrush — a thick, whitish coating of the tongue or mouth that's caused by a yeast infection and sometimes accompanied by a sore throat, diarrhea that lasts more than a week, headaches, lightheadedness, and/or dizziness.

ddNTPs - Dideoxynucleotides and abbreviated as ddNTPs.

They are chain-elongating inhibitors of DNA polymerase, used in the Sanger method for DNA sequencing.

They have a hydrogen at the 3’ carbon of the ribose sugar.