How does (inheritable) variation arise in any population?

Variation arise in any population by mutation , random mating between organisms , random fertilization , and crossing over between chromatids of homologous chromosomes during meiosis.

Explanation:

Genetic variation or Inheritable variation is a general estimation that identifies the existing genetic differences over the population. These differences take place in the DNA or Genes and each variation is known as an allele.

Thus Genetic variation is also defined as the variation in alleles of DNA or genes that takes place among and within the population. Each individual is adopted to its nature and environment.

The Genetic Variation is achieved by mutation, mating and fertilizing between random organisms and cross over of chromatids during meiosis(cell division).

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.

photosynthesis makes the glucose that is used in cellular respiration to make atp. the glucose is then turned back into carbon dioxide, which is used in photosynthesis. while water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.