It wants you to explain why its a chemical change. Signs of chemical changes are formation of gas bubbles, cloudyness, change in color or odor.
Answer: C) the genes of this phage were made of DNA.
Explanation: the experiment described above wherein a radioactively labeled bacteriophage was allowed to infect bacteria ultimately led to the conclusion that the genes of the bacteriophage under study were made of DNA (a biopolymer of deoxyribonucleic acid, which is a type of nucleic acid composed of four different chemical groups, called bases: adenine, guanine, cytosine and thymine). Simply put, the experiment shows that the genetic material of the phage is DNA.
Answer:
These structures that protect the sponges from most predators, but not turtles, are spicules.
Explanation:
Sponges <em>skeleton</em> is composed of <em>calcium carbonate and siliceous</em> micro-structures called <u>spicules</u>. Their morphology is so varied that it is used in taxonomy for identification and classification.
There are different kinds of spicules:
- <em>Monoaxonic spicule</em>: needle-shaped, straights or curves
- <em>Tetraxonic spicules:</em> they have four prolongations
- <em>Triaxonic or Hexaxonic spicules</em>
- <em>Poliaxonic spicules </em>
Two terms can be applied to any of these spicules kinds:
- <em>Megaspicules</em>: They are elongated and compose the main architecture of the sponge skeleton
- <em>Microspicules</em>: Variable in shape and size, with ancillary functions
Sponges have few predators thank to the spicule structures and their high toxicity. Many of them are capable of perforating soft tissues and producing urticant substances.
686.8 j is needed to burn 4.24 grans of pd.
