Which of the following most contributed to the large increase in world population that occurred around the 1800s to 1900s?

Which of the following most contributed to the large increase in world population that occurred around the 1800s to 1900s?

The development of agriculture and the domestication of animals. Which of the following most contributed to the large increase in world population that occurred around the 1800s to 1900s? More people lived due to the discovery of vaccinations and medical treatments for deadly diseases.

When the ovum and sperm cells unite and fertilization has occurred what has just been formed?

“The development of a human being begins with fertilization, a process by which two highly specialized cells, the spermatozoon from the male and the oocyte from the female, unite to give rise to a new organism, the zygote.”

What occurs during meiosis in which chromosomes sometimes fail to divide properly?

Aneuploidy is caused by nondisjunction, which occurs when pairs of homologous chromosomes or sister chromatids fail to separate during meiosis. The loss of a single chromosome from a diploid genome is called monosomy (2n-1), while the gain of one chromosome is called trisomy (2n+1).

What occurs during meiosis in which chromosomes sometimes fail to divide properly as a result the person may have 45 or 47 chromosomes?

Mitotic nondisjunction can occur due to the inactivation of either topoisomerase II, condensin, or separase. This will result in 2 aneuploid daughter cells, one with 47 chromosomes (2n+1) and the other with 45 chromosomes (2n-1). Nondisjunction in meiosis I occurs when the tetrads fail to separate during anaphase I.

Why is an extra chromosome bad?

Chromosomal abnormalities can have many different effects, depending on the specific abnormality. For example, an extra copy of chromosome 21 causes Down syndrome (trisomy 21). Chromosomal abnormalities can also cause miscarriage, disease, or problems in growth or development.

Can a weak sperm cause pregnancy?

Having a low sperm count decreases the odds that one of your sperm will fertilize your partner’s egg, resulting in pregnancy. Nonetheless, many men who have a low sperm count are still able to father a child.