Answer:
They have helical thickening of lignin in their walls to prevent collapse
Explanation:
the primary function of Xylem and its conducting vessels tracheids is to provide support and tranport water and minerals in plants.
Xylem vessels have layers of dead materials in the walls called LIGNIN. Lignin is a polymer; a very strong, hard materials that stop water passage through it,because it contains dead cells,
Therefore the presence of deposit of these strong impermeable, ligified walls in its walls prevent its collapse during mass flow of water of transpiration pull.
I think its a and b, but i dont know what kind of rock it is. my guess is a metamorphic or sedimentary.
Answer:
Limiting Reactant
Explanation:
Observe the answer choices:
A) Limiting Reactant; a limiting reactant, as can be seen from the name, is the reactant that <em>limits</em> the amount of products can be made. This is because the reaction can only go on if there is enough reactants. However, the limiting reactant is the one that will run out first, so it's going to be completely consumed.
B) Reactant; a reactant is the thing that is being consumed in a reaction. However, reactants aren't always completely consumed. There's something called an excess reactant, which is essentially the opposite of a limiting reactant in that when the limiting reactant is used up, there's still some excess reactant left - because it's in <em>excess</em> / there's more than enough remaining. So, this is incorrect.
C) Products are the ones that are created during the chemical reaction, so they aren't consumed in any way. Thus, this is wrong.
The answer is limiting reactant.
Hope this helps!
<span>Invertebrate<span>, </span>any animal that lacks a vertebral column, or backbone, in contrast to the cartilaginous or bony vertebrates. More than 90 percent of all living animal species are invertebrates. Worldwide in distribution, they include animals as diverse as sea stars, sea urchins, earthworms, sponges, jellyfish, lobsters, crabs, insects, spiders, snails, clams, and squid. Invertebrates are especially important as agricultural pests, parasites, or agents for the transmission of parasitic infections to humans and other vertebrates. Invertebrates serve as food for humans and are key elements in food chains that support birds, fish, and many other vertebrate species.Apart from the absence of a vertebral column, invertebrates have little in common. Indeed, they are distributed between more than 35 phyla. In contrast, all vertebrates are contained within a single phylum, the Chordata. (Phylum Chordata also includes the sea squirts and some other invertebrate groups.) Invertebrates are generally soft-bodied animals that lack a rigid internal skeleton for the attachment of muscles but often possess a hard outer skeleton (as in most mollusks, crustaceans, and insects) that serves, as well, for body protection.</span>
