Answer:
The problems that can be caused by Expansion or Contraction a;long with the solutions are:
Explanation:
- The railway tracks made of steel expand during the summer and contract during the winter. This can cause them to become curved during the summer thereby causing rail derailment.In order to prevent this, an air gap is kept in between the railway lines so that they get the space to expand without getting curved.
- The electric wires linking the telegraph posts are made up of metals and so they expand in the summer and contract in the winter, which can cause them to tear. This is why the wires are loosely fixed so that they can expand and sag in the summer and contract and tighten in the winter.
- Bridges are constructed with joints where some space is maintained to allow the easy expansion and contraction in summer and winter respectively.
Answer:
ummmmmm i think ..i.. its the right answer
Explanation:
Answer:
Protosomes
Explanation:
Protosome is a multicellular organism whose mouth grows before the anus from a primary embryonic opening which includesphyla mollusk, arthropod or annelid. Protosomes are developed by spiral cleavage during embryo development.
Protosome animals have bilateral symmetry and three germ layers. Some of the examples of protostomes are snails and slugs (mollusk), earthworms (annelids), and spiders, lobsters, barnacles (arthropods).
Hence, the correct answer is Protosomes .
Answer
True
Explanation:
The temperature in the bathypelagic zone, unlike that of the mesopelagic zone, is constant.
Answer:
Fraternal twins can be different genders because they are two completely different eggs getting fertilized; but even two same gender fraternal twins do not look completely alike. Whereas for identical twins since one egg is splitting into two, the two cells have the same exact DNA make up and chromosomes.
I also believe the technical part of it is to do with genetics, like ressesive and dominant genes, because they can be the same gender, ex. both girls and one has blue eyes, fair skin, and blonde hair, the other twin has brown eyes, black hair and tan skin. The parents could be part of the genes but there is also grandparents maybe the mom's mom has blonde hair and blue eyes, with fair skin. But the dad he has brown eyes, black hair and tan skin. The moms genes were recessive, but the grandma's genes were dominant.
I tried to explain it as best as I could I hope it helps!