During what phase of meiosis is the dna replicated?
prophase i
anaphase i
metaphase i
telophase i

The Crossover of chromosomes occurs during the prophase 1 phase of meiosis.  

Further Explanation

Cell division  

Cell division is the process in which cells within an organism undergoes division to give rise to new cells.

There are two types of cell division, namely:

Mitosis  

Mitosis is a type of cell division that occurs in the somatic cells or the body cells where cells divides to give new cells that are similar to the parent cell.

The daughter cells have the same number of chromosomes as the parent cells.

For example in humans the parent cells are diploid, 2n, while the daughter cells are also diploid, 2n. (Diploid means each cell has two pairs of chromosomes).

Meiosis  

This is a type of cell division that takes place in the gonads, or reproductive organs, in which cells divide to form daughter cells that differ genetically with the parent cells.

The daughter cells contain half the number of chromosomes, haploid, n, while the parent contain a diploid number, 2n, of the chromosomes.

Meiosis occurs in two phases, that is, meiosis I and meiosis II

During the process of meiosis several processes occurs that cause genetic variation among organisms. These processes include, crossing over, independent assortment of genes, among others.

Crossing over  

Cross over is the process that occurs during the prophase I phase of the first stage of meiosis known as meiosis I.  

During the process of crossing over, genetic material is exchanged between homologous chromosomes which enhances the genetic variation in organisms.

Keywords: Cell division, meiosis, mitosis, prophase I, crossing over

Learn more about:

Cell division:

Mitosis:

Crossing over:

Genetic variation:

Prophase 1 of meiosis:

Level: High school  

Subject: Biology

Chapter: Cell division  

Sub-topic: Meiosis

"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.