Answer:
The three-chambered hearts of amphibians and nonbird reptiles are facultative, allowing variation in blood flow through the heart.
Explanation:
In Anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Generally, the cardiac cycle occurs in two (2) stages;
I. Diastole : in this stage, the ventricles is relaxed and would be filled with blood.
II. Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.
All amphibians and reptiles except for crocodiles (having four-chambered heart) have three-chambered hearts, which typically comprises of a partially divided ventricle and two atria.
Hence, the correct statement about the three-chambered hearts of amphibians and nonbird reptiles is that, the three-chambered hearts of amphibians and nonbird reptiles are facultative, allowing variation in blood flow through the heart due to the partially divided ventricle.
Answer:
<h2>
Through production of news cell-surface proteins with a different molecular structure by each new generation. Letter B</h2>
Explanation:
The life cycle of theses paratises extracellular alternate between the salivary glands of the insect transmitter and the blood of the mammal. During the set prior to the entry into the host, the metacylic parasites express a dense over formed by the Variant Surface of Glycoprotein, after entering to the mammal host they transform into a morphology that stays in the bloodstream.
<em>The parasites have to manipulate hosts cells in order to avoid the production of antimicrobial molecules and to benefit from growth factor production.</em>
<em>Intracellular protozoa have a remarkable adaptive capacity as they are able to resist killing by remodelling the phagosomal compartments where they reside and by interfering with the signalling pathway that leads to cellular activation. </em>
B - They have different arrangements of atoms.
Answer:
6. Because of how old the rocks are
Explanation:
6. Sedimentary rock forms in layers because of the order they were formed. The older rocks will form first and as time goes on, rock forms above it to create a new layer, and so on.
