The right matches are :
A. bryophyte ==> 3.
B. pteridophyte ==> 2.
C. gymnosperm ==> 1.
D. angiosperm ==> 4.
These four types of plants are cormophytes.
Bryophyte is a terrestrial plant belonging to the family Bryophyta, which does not have a real vascular system.
Gymnosperms are the first order of didynamy containing phanerogamous plants whose eggs are not enclosed in closed carpels.
Angiosperms are plants whose seeds are enclosed in a closed ovary.
Pteridophytes produce neither flowers nor seeds but are vascular plants.
The laboratories have initiated Phase 1 clinical trials for the use of human pluripotent embryonic stem cells to treat paralyzed patients following spinal cord injury. The first step is to estimate the risks and tolerance of cell transplantation in a man. The fate of stem cells (multipotent or pluripotent) in the body is still poorly understood, and it is not excluded that uncontrolled cell multiplications occur, leading to the appearance of teratomas (tumor developed from pluripotent cells).
Advantages are:
* The safety of the cells also seems to be proven (in short term)
* Rats transplanted seven days after the injury had benefited from reactivation of myelinization of neurons by oligodendrocytes, attenuation of motor neuron loss and improvement of limb motor function.
The disadvantages are:
* Constraints of the ethical and religious order, it is necessary the consent and the approval of the donor and the recipient for the transplant to take place.
* The development of the technique is still new, there is a chance that side effects of the transplant appear years after the operation.
The answer is A. True.
Plankton includes a diverse group of organisms that live in the water but are not capable of active swimming against the water current. On the contrary, nekton<span> includes a diverse group of organisms that live in the water but are capable of active swimming without the help of the water current. A shark is capable of active swimming, therefore, it is the example of nekton.</span>
