Because some problems are not always small enough for one nation that can do it by themselves and need more helpo
Answer:
The four- chambered hearts of birds and mammals are best described as <u>homoplasies.</u>
Explanation:
In evolution, homoplasies are the trait shared in different species despite that their ancestors didn't have it at all. In other words, these are traits that can be gained or lost during evolution in different lineages independently. For example, wings of birds and wings of bats do the same function (help in flying) but they were not there in the ancestors so both animals developed these structures independently.
In the given example, birds and mammals have four-chambered heart but their ancestors have 3 chamber hearts. They evolved independently and developed 4 chamber heart. This might be due to several reasons. However, their ancestors didn't have the feature so it is an example of homoplasy.
Correct answer: "<span>D - it becomes glucose through the process of photosynthesis"
The atmospheric carbon is absorbed by plants in the form of carbon dioxide and used in the process of photosynthesis. Photosynthesis takes 6 carbon dioxide molecules and 6 water molecules to produce a molecule of glucose and 6 of oxygen. That's where most of the atmospheric carbon is used in.</span>
Answer:
Answered below
Explanation:
B cells are a type of white blood cells of a subtype called lymphocytes. They confer acquired or adaptive immunity. This means that B lymphocytes responses to infective microbes are from the memories of their previous encounter with the microbes or antigens.
B lymphocytes fight bacteria and viruses by making Y-shaped proteins called antibodies. These antibodies are specific for each pathogen encountered. They identify and lock on to the surface of invading pathogenic cells and mark and present them for destruction by other immune cells.
Oftentimes, these antibodies are enough to fight off most bacterial infections that we have and therefore there's no need for extensive treatment with drugs.
