1. a jar contains 100 marbles total. some are black. if you pull 4 marbles out and 1 is black
how many out of the 100 marbles would you guess are black?

The number of black marbles in a jar containing 100 marbles  is ;  25 black marbles

Given that:

Jar contains 100 marbles

out of every 4 marbles pulled, 1 marble  = black

∴ probability of picking a black marble = 1/4

Determining the number of black marbles contained in 100 marbles

= 1/4 * Total number of marbles

= 1/4 * 100 marbles =  25 black  marbles

Hence we can conclude that the number of black marbles in a jar  containing 100 marbles = 25 black marbles

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the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.