A. Ancestors of whales may once have been able to walk.
Answer:organs
Explanation:the body of multicellular organisms are organised into levels of organization.these levels increases in complexity.
The macromolecules makes up the organelles . organelles in turn makes up the cell.A group of similar cells at a certain location makes up an organ.for example the heart consists of a number of cells.
A group of organs which work together to achieve a specific function in the body , makes up the organs system.
For example the circulatory system of a while is made up of different connected organs - heart, blood vessels,to perform the function of transporting blood around it's body.this makes it an organ system.
Answer:
The correct answer is : oxygen
Explanation:
- Oxygen is carried in the blood by two means:
- About 2% of the oxygen is carried in the dissolved form in blood plasma and in the water present in the red blood cells (RBCs).
- Rest 98% of the oxygen is carried in bound form with the haemoglobin as oxy-haemoglobin inside the RBCs.
- RBCs lack nucleus. This place is occupied by hemoglobin molecules that binds to oxygen and form oxy-hemoglobin.
- This increases the capacity of each RBC so that it can carry more oxygen to all the parts in the body.
