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.
By the time the bubbles rose to the surface of the ocean, the bubble model proposes that simple organic molecules had formed inside. The bubbles burst upon reaching the surface, releasing those molecules into the air.
The process that is responsible for causing menstruation is called menstrual cycle. Menstrual cycle is the natural change that occurs specifically in the ovaries and uterus or in the female reproductive system that gives possibility to pregnancy. This process is required for the ovocytes to be produced, and also for the uterus to be prepared for pregnancy.