Answer:
B
Explanation:
Homeostasis is defined as a regulating process to maintain balance within the body systems. It is to maintain the interior conditions and ensure that nothing goes wrong or out of the ordinary. Choice B matches this.
A is incorrect because homeostasis can occur <em>both</em> at the cellular level <em>and</em> at the system level.
C is incorrect because homeostasis actually occurs in prokaryotes, as well.
D is incorrect because both A and C are wrong.
Hope this helps!
Fern spore germinates into prothallus.
Explanation:
Ferns are members of phylum pteridophyta, the vascular cryptogams.
These are first land plants which are known to have a distinct conducting system of xylem and phloem.
They reproduce by forming spores that germinates into a heart shaped gametophyte.
The gametophyte of the fern is called prothallus.
The heart shaped gametophyte has root like structure called rhizoids.
These rhizoids anchor the gametophyte to the substratum.
The definition of vestigial structures is structures that appear to have lost their necessity throughout evolution so the answer would be true.
Eukaryotic cells are larger than prokaryotic cells and have a “true” nucleus, membrane-bound organelles, and rod-shaped chromosomes. The nucleus houses the cell's DNA and directs the synthesis of proteins and ribosomes.
So..the answer should be D. Eukaryotic cells have a true membrane-bound nucleus and prokaryotes do not
All cells have a plasma membrane, ribosomes, cytoplasm, and DNA. Prokaryotic cells lack a nucleus and membrane-bound structures. Eukaryotic cells have a nucleus and membrane-bound structures called organelles.
So..it can't be C. or A. or even B.
Correct me if I'm wrong.
1. PbO is a possible formula units, since O has charge of 2- and Pb can have a charge of 2+ or 4+, if it uses the 2+ ion, the charges will balance out to form PbO. Li+ and B(3-) would have Li3B, Al(3+) and Pb(2+) are both positive charges and would not balance out, Cl- and O(2-) are both negative charges and would not balance out.
2. Iodine is a halogen, so it has a charge of -1. Calcium is an alkaline earth metal in Group 2, so it has a charge of 2+. Therefore, if they were to form a formula unit, the resultant would be CaI2 (2 iodine atoms of 1- charge are needed to balance out the 2+ charge on the calcium atom).
3. Strontium is an alkaline earth metal with a charge of 2+, while phosphorus has a charge of 3-. Therefore, to balance the charges out, we would need 3 atoms of strontium and 2 atoms of phosphorus. This would give the formula unit of Sr3P2.
