Because it is polar and it is to large to cross the membrane and because the concentration gradients are to strong so they have to be diffused.
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Yes. True vertebrates have a true head that develops from a neural crest of cells and hard structures surrounding the notochord.
The neural crest, which forms early in the development process in vertebrate embryos, is a fold on the neural plate where the neural and epidermal ectoderms converge. As an embryo grows, the neural crest produces neural crest cells (NCCs), which can differentiate into a variety of different cell types and contribute to tissues and organs.
The notochord is a temporary structure that plays a crucial role in higher animals. It secretes substances that communicate with all neighbouring tissues, telling them where they are and what will happen to them.
Therefore, True vertebrates have a true head that develops from a neural crest of cells and hard structures surrounding the notochord.
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Answer:
nerve cells (a)
Explanation:
it is muscle cells but nerves and muscles go hand in hand
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Answer:
Iodine
Explanation:
This is a trace element needed for the synthesis of the two thyroid hormone ; T4- thyroxine and T3-triiodothyronine. Four iodine molecules are added in T4 synthesis, and three for T3 synthesis. Generally T4 is the major hormone produced, but biologically transformed into active form T3.
Iodine majorly and selenium are the two trace elements needed for thyroid hormones synthesis. Therefore required amount of iodine is important in daily diet. iIn adequate supply of this leads to under production of iodine called hypothyroidism. poor brain development ( especially in kids),and goiter.
Sea foods . eggs, poultry seaweeds are rich sources of iodine.
Conversely, when excessive amount is present in the blood, autoimmune thyroid diseases can occur,including cancer developments in the thyroid gland due to hyper cell activities.
Decreasing first and then growing happening to the population because at every year 10.20 percent population is growing.
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How can you figure out a population's growth rate when there are births and deaths?</h3>
The net reproduction rate (r) is computed as follows: r = (births-deaths)/population size, or simply multiply by 100 to get in percentage terms. Because the population has grown so much, many more people have been added. When a population grows at a steady rate year after year, this is referred to as exponential growth.
Migration is the the number of immigrants minus the number of emigrants over a given time period, divided by the number of person-years lived by the receiving country's population during that time period. It is calculated as the number of net migrants per 1,000 people.
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