What would be the result if crossing over did not happen during meiosis in humans?

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?

What will happen if two of the base pairs of the stand of the dna are switched