The answer is A. Amniotic sac
Where is the model? There is no picture.
<h2>Explanation:</h2>
Membranes are semipermeable lipid bilayers. Permeability refers to the ease with which molecules cross biological membranes. Because of the chemical and structural nature of the phospholipid bilayer (hydrophobic core), only lipid-soluble molecules are able to freely pass through the lipid bilayer because it attracts these non polar molecules.
Water soluble or hydrophilic molecules cannot pass through these lipid membranes because hydrophobic bilayer repels hydrophilic molecules. Ions and large polar molecules cannot pass through the lipid bilayer.
But more specifically, whether a molecule can pass through the membrane depends on its size and its electrical nature.
Answer:
Basic characteristics of Sponges:
Sponges belong to phylum porifera. They are simple multi-cellular aquatic animals. They have pores in their body thats why they look like sponge we use in kitchen. These pores are known as ostia. The body cavity is known as spongocoel, which open to out side through large pore known as osculum. Their body is composed of two layers, choanocyte and pinacocyte. Choanocytes are flagellated cells having spikes which help in movement of water into body and aid in capturing of food particles. The skeleton is made up of calcium carbonate or silica. A jelly like substance called as mesoglea is present between pinacocyte and choanoderm.
<span>General characteristics of Archeocyathans:
</span> The term archeocyathans is a Greek word for "ancient cup". They have a single common ancestor and became one of the planet first reef animals. S<span>pecies of archeocyathans is divided into two classes, six orders, 12 suborders, 120 families and nearly 300 genera. They are associated with carbonate sedimentation.They generally lived in shallow water with photic zone. Their fossils often co-occured with fossils of cyanobacteria. </span><span>These are marine organisms whose fossils record dated back to late Precambrian and early Cambrian period. They are most closely resemble to calcareous sponges. Their structure s are conical or tubular in shape and superficially resembles horn reefs. They have world wide distribution and found in Australia, Antartica, Spain, Cubec, New york and California,</span>
In the fastball reproduction, my response times started to get littler after some time. Variables that may have ascribed to the variety I saw more than ten trials were that I comprehended what to do simply after the first trial and that I was expecting the ball more.
