1. Muscles are grouped in antagonistic sets because:
A. muscles cannot lengthen by themselves.
B. muscles push but cannot pull.
C. they do not like one another.
D. there is an increase in metabolic efficiency if they are present in antagonistic sets.
is it A
2. In most women's menstrual cycles, ovulation occurs:
A. at the onset of the flow.
B. halfway through the cycle.
C. just after sexual intercourse.
D. just following the last cycle.
is it A
1. To determine the correct answer, let's break down the options:
A. Muscles cannot lengthen by themselves: This statement is not entirely accurate. Muscles can indeed lengthen on their own, through a process called muscle extensibility. However, this option highlights an important aspect of the muscle's ability to contract and relax.
B. Muscles push but cannot pull: This statement is not entirely accurate either. Muscles can both push and pull, as they work in pairs or groups to create movement in opposing directions. So this option is not the correct answer.
C. They do not like one another: This option is unrelated to the physiological function of muscles and, therefore, not the correct answer.
D. There is an increase in metabolic efficiency if they are present in antagonistic sets: This statement accurately explains the reason why muscles are grouped in antagonistic sets. When muscles work in pairs, one muscle contracts (agonist) while the opposing muscle relaxes (antagonist). This arrangement allows for more efficient movement and conserves energy by reducing the workload on a single muscle. Therefore, option D is the correct answer.
So, the correct answer is D: There is an increase in metabolic efficiency if muscles are present in antagonistic sets.
2. To find the correct answer, let's analyze the options:
A. At the onset of the flow: This option refers to the beginning of the menstrual cycle when bleeding occurs. However, ovulation typically occurs midway through the cycle.
B. Halfway through the cycle: This option is accurate. In most women's menstrual cycles, ovulation occurs around day 14 (counting from the first day of the cycle), which is approximately halfway through a typical 28-day cycle.
C. Just after sexual intercourse: This option is not accurate. Ovulation does not occur immediately after sexual intercourse; rather, it happens at a specific time in the menstrual cycle.
D. Just following the last cycle: This option is not accurate either. Ovulation occurs during the current menstrual cycle, usually around the middle, and is not directly related to the previous cycle.
So, the correct answer is B: Ovulation occurs halfway through the menstrual cycle for most women.