Answer:
Evolution occurs due to change in the characteristics of life.
Explanation:
The shared characteristics of life provide evidence for evolution. These shared characteristics are reproduction, homeostasis, heredity, growth, development and adaptation which occurs through evolution. The evolution mainly occurs due to changing environmental conditions. Some sea organisms such as whales evolve from land animals having four legs through the process of evolution. The environment of sea is responsible for the formation of gills and other body structure in order to survive in the water.
The common atrium is subdivided into a left and right atrium by an interatrial septum, which consists of two parts: the septum primum and the septum secundum that partially overlap.
What is septum primum and septum secundum?
- The septum primum, which divides the right from the left, is a structure inside the primitive atrium.
- In the direction of the endocardial cushions, this septum descends.
- The foramen primum, a hole in this septum, keeps the blood flowing through the heart.
- The foramen secundum develops as the foramen primum shrinks in size.
What is the purpose of septum secundum?
- A muscular flap called the septum secundum plays a significant role in heart growth.
- It has a semi-lunar form and develops from the atrium's upper wall to the right of the septum primum and ostium secundum.
- It is crucial for the foramen ovale to close after birth.
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<u>The correct question is -</u>
The common atrium is subdivided into a left and right atrium by an interatrial septum, which consists of two parts: the septum ______ and the septum ______ that partially overlap.
For the answer to the question above, I think that Few Fossils exist from this time because the animals were all soft-bodied. Most of the animals dissolve or decompose immediately and turn to dust because they are soft-bodied.