Organisms at higher trophic levels tend to be fewer in number than those at lower trophic levels.Please select the best answer from the choices provided

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PLEASE HELP I'll MARK THE BRAINLIEST1.) A vessel that carries oxygen-rich blood to the heart muscle is called a(n): *

A.) Coronary Artery

B.) Vein

C.) Ventricle

D.) Atrium


2.) A group of cells that receives messages about the body's oxygen needs and sends out signals to adjust the heart rate is called the: *

A.) Atrium

B.) Lymph Node

C.) Valve

D.) Pacemaker


3.) Blood components that helps the body control bleeding are: *

A.) Hemoglobin

B.) Red Blood Cells

C.) White Blood Cells

D.) Platelets


4.) Plasma is mostly composed of: *

A.) Blood Cells

B.) Water

C.) Proteins

D.) Hemoglobin


5.) Which of the following is NOT a characteristic of a vein? *

A.) Valves prevent backward flow of blood

B.) Returns blood to the heart

C.) Walls are one cell thick

D.) Walls are generally thinner than those of arteries


6.) The largest artery in the body is called the: *

A.) Aorta

B.) Atrium

C.) Pacemaker

D.) Coronary Artery


7.) The network of vessels that returns fluid to the bloodstream is called the: *

A.) Lymphatic System

B.) Veins

C.) Arteries

D.) Circulatory System


8.) Hemoglobin is a protein that binds easily to: *

A.) White Blood Cells

B.) Oxygen

C.) Fibrin

D.) Platelets


9.) Which of the following structures pumps blood into arteries leading to the lungs? *

A.) Right Atrium

B.) Left Atrium

C.) Right Ventricle

D.) Left Ventricle


10.) Which of the following structures is NOT part of the cardiovascular system? *

A.) Heart

B.) Blood Vessels

C.) Brain

D.) Blood


11.) True/False: The force of the heart's contracting atria causes blood pressure. *

A.) True

B.) False


12.) True/False: Capillary walls must be very thick to withstand the high force of blood pumped by the heart. *

A.) True

B.) False


13.) True/False: White blood cells defend the body against disease. *

A.) True

B.) False


14.) True/False: Blood travels in two directions in the body. *

A.) True

B.) False


15.) True/False: Blood types are determined by proteins known as marker molecules that are on red blood cells. *

A.) True

B.) False


16.) Fill in the Blank: The right and left __________________ are the two lower chambers of the heart. *


17.) Fill in the Blank: A sphygmomanometer is an instrument that measures ____________________________. *


18.) Fill in the Blank: A flap of tissue that prevents blood from flowing backward is a(n) ______________. *


19.) List two of the three main roles of the cardiovascular system: *


20.) Tell me anything else that you learned in science about the cardiovascular system:

What might happen to a coral reef organism if it were placed in a kelp forest ecosystem

Which phrase describes the chromosomes by the end of prophase of mitosis? A.
The chromosomes have stretched out.

B.
The chromosomes have separated at the centromere.

C.
The chromosomes are pulled to opposite sides of the cell.

D.
The chromosomes have coiled and become more compact.

Gravity is the force by which a planet or other body draws objects toward its center. The force of gravity keeps all of the planets in orbit around the sun. What does the force of gravity depend on?

How does dna give us our traits?

The results of investigating a technological design A. can be presented orally, in writing, or both. B. can be presented only in writing. C. can be presented only orally. D. cannot be presented orally or in writing.