Which of the following statements is true for all types of passive transport? Group of answer choices Ions never cross the plasma membrane by passive transport. Only small polar molecules are able to cross the plasma membrane. The concentration gradient is the driving force. Proteins are needed to transport molecules across the membrane.

The concentration gradient is the driving force.

Explanation:

Passive transport of substance occurs when they are moved from the region of their higher concentration to that of their lower concentration. The concentration gradient is the difference in the concentration of substances between two regions or across the membrane. The concentration gradient of substances drives their passive movement. The passive movement of substances does not use metabolic energy.  Simple diffusion and facilitated diffusion are two examples of this transport.

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"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."