Answer:
The form of cell to cell signalling that is been used is ENDOCRINE.
Explanation:
There are four ways by which cell signalling occur in the body, these are: endocrine, paracrine, autocrine and direct signalling.
Endocrine signalling is the biochemical process by which hormone secreting glands release hormones into the blood streams and that hormone has effects on target organs that are located far away from it. Endocrine hormones are usually stable and their effects usually last for long time.
D. all of the above
this sounds a lot more like geography than biology by the way
PART 1
1. They nurse their young with milk produced by mammary glands.
2. <span>There are international laws and treaties that protect marine mammals.
3. </span><span>Unfortunately, many marine mammals are considered endangered species and there are still threats to most of their populations, such as illegal hunting, pollution, climate change, and habitat loss.
4. T</span><span>hey have adapted to living all or part of their life in the ocean.
5. </span><span>To keep warm in the ocean, most of them depend on a thick layer of blubber (or fat).
6. </span><span>To be able to stay under water for long periods, they store extra oxygen in their muscles and blood.
7. </span><span>They also have more blood than land mammals in proportion to their body sizes, can direct their blood flow to only their vital organs (such as their heart and lungs), and can slow their heartbeat down so they are using less oxygen in a dive.
PART 2
</span>Kingdom: Animalia
<span>Phylum: </span>Chordata
<span>Class: </span>Mammalia
<span>Order: </span>Cetacea <span>The Order Cetacea is the group of marine mammals that includes the </span>cetaceans<span> - the whales, dolphins and</span>porpoises.<span>There are </span>86 species<span> of cetaceans, and these are divided into two suborders - the mysticetes (</span>baleen whales, 14 species) and odontocetes (toothed whales<span>, 72 species).</span>
Hope this helped...Good luck!
Answer: Sexual reproduction
Explanation:
First, you should understand that mutation (an change in the base-pair sequence of the genetic material, DNA) is the original source of all genetic variation; as such whatsoever will alter the frequency of alleles, even if it is evolution, it relies on mutation.
In contrast, sexual reproduction does not change the frequency of alleles in the gene pool, rather it ensures constancy through the meiotic cell division process
Answer:
C) Three hydrogen bonds will form with guanine.
Explanation:
Generally the DNA molecule is made up of Purines bases of Adenine and Guanine,and Pyrimidine of Cytosine and Guanine.However,RNA contains a different pyrimidine of Uracil.Thus the pairing is A-U am C-G.The uracil replaces Thymine.
The structure above is a Pyrimidine,because it is made up of single ring structure(an heterocylclic aromatic structure) compare to double structure of purines. Heterocyclic means it is ring form.Aromatic means it has resonance bonds which shift with the rings for stability.
It is also contains of two substitutes at position 4 of the ring structure (amineNH2) and at 2 which is the Keto group(=0).Therefore the structure is Cytosine.
In RNA structure the Cytosine pair with the three hydrogen bonds with guanine,while Adenine pair with Uracil.This ensures stability of the RNA structure.
