Answer: The correct answer is- B)They are single cells that lack a nucleus and tend to live in extreme conditions.
Archaebacteria are the oldest life forms, which are found on earth. They are unicellular ( made up of one cell) prokaryotes ( lacking nucleus and membrane bound subcellular organelles) belonging to the kindom, Archea. They are found in extremely harsh environmental conditions such as hotsprings, boiling mud surrounding volcanoes.
Example- Methanogens, halophiles.
Thus, option B) is the right answer.
<span>When comparing lakes and oceans, most lakes have : A ) lower levels of salt
-Hope this helps.</span>
Answer: e. 2.5 ml
Explanation:
According to the dilution law,

where,
= concentration of stock solution = 20X
= volume of stock solution = ?
= concentration of required solution= 1X
= volume of required solution= 50 ml


Thus 2.5 ml much of a 20X tricaine stock solution is needed to dilute in order to make your solution.
Answer:
Orca inhaled oxygen and exhaled carbondioxide just like humans and other mammals.
Orcas is a type of whale which breathe air through their lungs not gills. They can't inhale oxygen from water, it comes to the surface in order to inhale oxygen and exhale carbondioxide.
In Orca breathing is not an automatic reflex but a conscious act due to the environmental condition. When orcas come to the surface to breathe they must quickly expel the carbondioxide gas and inhale oxygen into the lungs so we can conclude that Orca breathe just like humans and other mammals.
Explanation: