"cutting down trees to build new buildings and roads", "factory and automotive emissions causing acid rain" and "redirecting and storing freshwater behind dams" exemplifies a way in which humans modify ecosystems. The correct option among all the options that are given in the question is the last option or the fourth option.
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<u>cardic muscles:</u> are present only in the heart .single cell is not very strong by itself, millions of cardiac muscle cells working together are easily able to pump all of the blood in the body through the heart in less than a minute. Cardiac muscle cells have a branched shape so that each cell is in contact with three of four other cardiac muscle cells.
<u>characteristics of cardic muscles: </u> one nucleus ,striated, involuntary, branched and joined to one another by intercalated discs that contain gap junctions for depolarization between cells and hold the fibers together when the heart contracts.
The Internal skeleton of the porcupine gives shape and structure to the porcupine.
The stem of the rose plant provides support to the plant and serves to transport nutrient and water in the plant.
<h3>What a skeleton?</h3>
A skeleton is a rigid structure found in living organisms which provide structure and shape to the living organism.
Skeletons are found in animals.
Skeletons present in animals are of two types:
- Internal skeletons also known as endoskeletons
- external skeletons also known as endoskeletons
The Internal skeleton of the porcupine gives shape and structure to the porcupine. It also serves as a point of attachment to muscles in order to enable movement.
Stems are present in plants.
Stems serve various purposes in plants such as:
- transport of nutrients and water
- storage of food and water
- provides support and structure to the plant.
Thus, the stem of the rose plant provides support to the plant and serves to transport nutrient and water in the plant.
In conclusion, the internal skeleton of animals and the stem of plants both provide shape and structure to the respective organisms.
Leran more about internal skeleton and plant stem at: brainly.com/question/840794
brainly.com/question/11171631
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Answer:
fter 8 weeks of pregnancy it's called the fetus
