The correct answer is A.
Oswald Avery applied several biochemical techniques to large cultures of bacteria in order to extract and purify the "transforming principle". Their experiments showed that most probably the "transforming principle" was DNA. One of the observations leading to this conclusion was that enzymes that degrade proteins or RNA (such ribonucleases) had no effect on the "transforming principle". On the contrary, enzymes degrading the DNA destroyed the extract's transforming capacity.
Variations can be genetic or environmental, the traits are passed from one generation to other generation of snail is from from both parents to offspring and through the environment.
The correct answer is C.
Explanation:
Genetic variation in an organism is passed to the offspring by its parents.
environmental variation is the the result of different environment with which individual adapt.
Natural selection is a process in which a suitable trait which is well adapted to the environment is passed on tho future generations.
Genetic variation is the change in DNA or gene of the individual trait. The tree snails having different pattern in their shells is due to the habitat they are living in.
The snails which have well adapted to the environment are able to reproduce and pass on the traits to their progeny. The variation is due to the traits passed from parents through the environment also.
Answer:
natutal resources are those which is not made by anyone
human made resources are those made by human or artifical things