<span>Filtration
Urea is the cellular waste product that the kidneys remove from the blood.Kidneys are the two bean shaped organs that has several functions to keep the body healthy. It not only removes urea from the blood, but also helps in the formation of urine and maintaining the fluid level of the body. The two kidneys are placed on the two sides of the spinal cord. The blood enters the kidney through the renal artery. The nephron within the kidneys mainly take out the waste products and the excess water from the blood and purifies it.If the kidneys of a person fail to work properly then it becomes important to perform dialysis for taking out the waste materials from the blood.</span>
Hihi!
Embryonic stem cells <span>are capable of only limited differentiation! They</span><span> can become all cell types of the body because they are </span>pluripotent<span>. Also a</span>dult stem cells<span> are thought to be limited to differentiating into different cell types of their </span>tissue<span> of origin.</span>
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-Jailbaitasmr
The first land animals had to adapt to this whole new set of conditions that were significantly different than the ones in the water.
One of the biggest challenges was to protect the embryo in these new harsh conditions. The amphibians and members of earlier lineages such as fish are dependent on water for their reproduction, but reptiles, birds, and mammals have developed the amniotic egg during the course of their evolutionary history enabling them to produce offspringing on the ground.
Members of this group either carry their offspring inside the female's womb or lay eggs that are protected with an outer tough layer. Both the young in the womb and the ones inside an egg are protected but the embryonic membranes amnion and chorion that contain water and nutrients necessary for the development of the embryo and therefore are called amniotes.
Answer:
The correct answer is option b. they must occur under carefully controlled conditions found in the laboratory.
Explanation:
Scientific experiments are well organized and step by step method to validate or test if a hypothesis is valid or not. It includes observation, test, analysis of the data and conclusion. The results are always useful even if hypothesis rejects.
Every experiment should be well documented to establish and reviewing purposes. It is not a compulsion for a scientific experiment to take place in the lab in controlled conditions.
Thus, the correct answer is option b. they must occur under carefully controlled conditions found in the laboratory.