Answer:
Common examples include carbon, sulfur, oxygen, iron, copper, aluminium. Elements are represented by symbols. Compounds are substances made from atoms of different elements joined by chemical bonds. They can only be separated by a chemical reaction.
Explanation:
Substances can be categorised as either elements or compounds. Both of these are made up of atoms, the only difference is an element is made of one type of atom whereas compounds are made of two or more different types of atoms.
Answer:
Because flu viruses evolve so quickly, last year's vaccine may not protect you from this year's viruses. New flu vaccines are released every year to keep up with rapidly adapting flu viruses.
Answer:
did you ever get the answer to this because i need it
Explanation:
Claim: Whales evolved from land mammals to water mammals.
Evidence: The first whales evolved over 50 million years. One of the first whales, such as Pakicetus, were land animals with long skulls and carnivorous teeth, much like many adaptable land mammals back then and today.
Answer:
fluid-filled cavity
Explanation:
Rhynchocoel is a fluid-filled tubular cavity present in the organisms of the phylum Nemertea. This cavity lies above the intestines of these organisms in the lower body.
Nemertea is a phylum composed of worms that can be found in shallow water.
These worms have already been classified as a branch of the Flatworms (such as Planarians), with which they are often confused. But recent embryological and molecular evidence points to a phylogenetic relationship with mollusks and annelids. They remind the Flatworms to be non-segmented flat worms. But unlike these, they have a complete bowel with mouth and anus, and a closed vascular system. The article on Planarians can be accessed here.
