An astronomical unit (AU) is the approximate distance from the earth to the sun. The answer is D.
Answer:
The correct answer is - option A.
Explanation:
Protists are single-celled eukaryotic organisms and usually move by cilia, flagella. Generally, they lack cell walls however, some forms may have a cell wall. They have organelles including a nucleus and may have chloroplasts, so some will be green and others won't be. They also contain the mitochondria for energy purposes.
Thus, laura should place the organism she found in the Protista biological kingdom according to their characteristics.
Answer:
The trachea, bronchi, and bronchioles are involved in conduction. Gas exchange takes place only in the lungs. Lung tissue consists mainly of tiny air sacs called alveoli, which is where gas exchange takes place between air in the alveoli and the blood in capillaries surrounding them.