Answer:
1. Carbohydrates - It serves several key functions in your body. They provide you with energy for daily tasks and are the primary fuel source for your brain's high energy demands. Fiber is a special type of carb that helps promote good digestive health and may lower your risk of heart disease and diabetes.
2. Protein- You use protein to make enzymes, hormones, and other body chemicals. Your body also uses protein to build and repair tissues. Protein is an important building block of bones, muscles, cartilage, skin, and blood.
3. Lipids - This is essential for all life on Earth. They play many important roles in maintaining the health of an organism. Arguably the most important function lipids perform is as the building blocks of cellular membranes. Other functions include energy storage, insulation, cellular communication and protection
4. Nucleic acids are very important for cell functioning, and therefore for life. There are two types of nucleic acids, DNA and RNA. Together, they keep track of hereditary information in a cell so that the cell can maintain itself, grow, create offspring and perform any specialized functions it's meant to do.
The homo erectus is the most common ancestor with modern humans
Answer:
In humans, genetic variations are caused because humans reproduce by a sexual life cycle which is termed as meiosis. In such a life cycle, the offspring receives half the chromosomes from the mother and half from the father. Crossing over and random assortment of chromosomes are two phenomenons which occur during meiosis. Due to these two phenomenons, genetic variations are caused.
During crossing over, the exchange of DNA segments between the homologous chromosomes takes place which brings about the genetic variations.
B) cell because all living things are made up of cells
<u>The heart is a cone-shaped muscular organ located within the mediastinum of the thorax.</u>
The mediastinum is the space lined with membranous tissue between the lungs. The mediastinum contains not only the heart but also the great vessels (pulmonary artery, aorta, pulmonary veins, and the superior and inferior vena cava), as well as parts of the esophagus and the trachea.
<span><u>Its apex rests on the </u><u>diaphragm</u><u> and its superior margin lies at the level of the </u><u>2nd</u><u> rib.</u>
</span>
The apex of the heart is the conical area created by the confluence of the ventricles, but mainly by the left ventricle. It rests on the diaphragm. The superior margin of the heart, also known as the base, lies at the level of the second rib.
<span><u>Approximately two-thirds of the heart mass is seen to the left of the </u><u>midsternal border</u><span><u>.</u>
</span>
This is because to the left of the midsternal border lies the left ventricle which comprises most of the heart mass as the left ventricle is the one responsible for pumping blood throughout the systemic circulation and significant pressure should be overcame; resulting to the physiologic hypertrophy of the left ventricle.
</span><span><u>The heart is enclosed in a serosal sac called the </u><u>pericardium</u><u>. The loosely fitting double outer layer consists of the outermost fibrous pericardium, lined by the parietal layer of the serous pericardium.</u></span>
The pericardium is one of three layers of the heart (other ones being the myocardium and the endocardium); and is the outer layer of the heart. The pericardium is composed of two tissues, the fibrous pericardium and the serous pericardium. The pericardium functions to lubricate the movement of the heart by the action of the pericardial fluid.
<span><u>The heart has </u><u>four</u><u> chambers. R</u></span><span><u>elative to the roles of these chambers, the </u><u>atria </u><u>are the receiving chambers, </u></span><span><u>whereas the </u><u>ventricles </u><u>are the discharging chambers.</u>
</span>
The four chambers of the heart are namely the right atrium, right ventricle, left atrium, and the left ventricle. Venous blood goes to the right atrium via the vena cavas then to the right ventricle via the tricuspid valve; then to the pulmonary circulation via the pulmonary artery where it will be oxygenated. From the pulmonary circulation, the left atrium will receive the oxygenated blood via the pulmonary veins then to the left ventricle via the mitral valve where it will be pumped to the systemic circulation via the aorta.