Answer:
The cell membrane is semipermeable because allows only certain molecules to pass through.
Explanation:
Semipermeability is a common property of cell membranes, due to their predominantly lipid composition, which gives them a hydrophobic character.
The cytoplasmic membrane is constituted by a double layer of lipids, in addition to structural proteins and glucides, which prevent the entry of polar or charged molecules. This characteristic allows lipids and small molecules without charge to pass freely through it.
Regarding the other options:
<em> A. Cell membranes are associated with lysosomes, structures that contain enzymes. However, this characteristic is not related to semipermeability.</em>
<em> C. They allow the passage of small molecules - devoid of charge - through them.</em>
<em> D. Not all non-polar molecules pass through, as some need a transporter.</em>
<span>The two basic molds are: Expendable
mold and permanent mold. </span>
Molding is a
process where a rigid frame (mold) is being used to manufacture by shaping liquid
or pliable raw materials. However, molding is synonymous to casting; casting is
a process where a liquid metal is delivered into a mold which contains a hollow
cavity of the intended shape.
Expendable mold casting can be classify as
sand, plastics, plaster which make use of non-reusable or temporary molds while Permanent mold casting is a metal
casting process that use reusable molds.
Answer:
option D
Explanation:
Negative feedback is a mechanism in which function of a cell or an organ is decreased. It lessened the output of a system and maintain system function which is known as homeostasis. It is a regulatory mechanism of normal physiology. Some of examples are
blood sugar level regulation, regulation of blood pressure, thermoregulation and many more.