Natural selection could not occur without environment, and a act on animal.
Multi cellular organisms are composed of many cells whereas unicellular organisms are composed of single cell. Multicellularity is indeed a progressive attribute of evolution where cells form tissue which forms organ and then organ system and finally an organism. Both multi cellular and unicellular organisms has advantages and disadvantages of their own. One of the main disadvantage of multi cellular organisms is that due to such a complex composition and functioning they require a large amount of energy for their maintenance and survival. Different organs and system require a huge amount of energy when it comes to comparison with unicellular organisms. A large amount of energy is also wasted in all these life processes. Though multi cellular organisms can survive in a variety of environmental conditions but then also their survival is difficult than any unicellular organism.
Answer:
recombinant DNA
A strand of DNA formed by splicing DNA from 2 different organisms is called recombinant DNA
Explanation:
Using the techniques of recombinant DNA technology, certain enzymes known as restriction enzymes capable of cleaving double stranded DNA in the plasmid of bacteria genomes (other organisms like eukaryotes can also be used) are used to obtain specific sequences of DNA bearing desirable traits in the both organisms.
Once the two DNA fragments have been obtained, another enzyme known as DNA ligase is used to seal the point of splicing, thereby constructing a single DNA from the two organisms.
This single DNA is known as Recombinant DNA
Answer:
Oxygen enters the body in the mouth and nose, passes through the larynx and the trachea. The trachea splits into two bronchial tubes, which lead to smaller tubes that lead to 600 million alveoli, which are small sacs surrounded by capillaries. The capillaries take oxygen into the arteries, and the oxygen-rich blood is then pumped into every cell of your body. Once the oxygen has been absorbed, carbon dioxide and water are eliminated through the lungs.
Explanation:
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<span>It is the variable in an experiment is not directly altered</span>
