Photosynthesis is a process in which a plant uses sunlight to create food, using CO2 and water.
I mean, there's plenty of differences between muscle and nerve cells. For one, they serve different functions. Nerve cells react and send stimuli rapidly through action potentials, functioning in the nervous system and allowing the brain to communicate with the rest of the body, while muscle cells allow muscles to move. Another difference is the structure of the cells, with nerve cells having dendrites, axons, and neurotransmitters to assist in the firing of action potentials. You're going to have to be a little more specific, I can't really help you any more with such a broad question.
This change in chromosome number is the result of B. Fertilization. Both of the individual gametes from the male and female combine together to produce a zygote or developing offspring that is diploid in most cases, and possess both sets of genetic content or chromosomal information, one from each parent.
The correct option is this: HAS THE CLAIM BEEN TESTED NUMEROUS TIMES BY MORE THAN ONE SCIENTISTS.
For a claim to be accepted has been valid in the science world, it must have been tested several times by many scientists who obtain the same results. Having a uniform result about a phenomenon is usually considered an important factor when examining the validity of a claim.