A contaminant is any environmental agent -biological,chemical or physical that causes damage.
Answer:
They are produced or originated from an epithelial sheet(like the endocrine glands) but will never lose the duct connecting them to the free surface of the epithelial sheet (surface of the skin or lumen of the open body cavities. They transport their product through a duct on the epithelial surface.
They transport their product through a duct on the epithelial surface.
using test tube tongs to handle the hot test tubes
checking the beaker for chips prior to heating on the hot plate
turning off the hot plate after use
Answer:
The correct answer is A and D
Explanation:
According to Russell's conception that lies in natural proton gradients. He states that Four billion years ago, alkaline fluids bubbled to produce mildly acidic oceans (As CO2 levels were about a thousand times higher, and it reacts with H2O to form carbonic acid, rendering the oceans mildly acidic). Acidity is just a measure of proton concentration, higher in the oceans than in vent fluids. This difference has given rise to a natural proton gradient across the vent membranes that had the same polarity (outside positive) which is similar to the electrochemical potential as modern cells have. This might be the reason that last universal common ancestors of all the three domains have evolved proton pumps.
<h3>Correct answer choice is:</h3><h2>B. Populations increase and decrease in a regular predictable pattern.</h2><h3>Explanation:</h3>
A population cycle in biology is a process where populations increase and decrease over an anticipated duration of time. There are many classes where population figures have logically anticipated models of reform although the full incentives for population cycles are one of the significant unsolved environmental difficulties.