Answer:
B.
Explanation:
Because a Longitudinal wave is a wave vibrating in the direction of propagation.
Ans.
Testes and ovaries are male and female reproductive organs, respectively. These organs are similiar as testes produce male gametes or sperms by the process of spermatogenesis and ovaries produce female gametes or ova by the process of oogenesis.
These gametes fuse together to form zygote that develops into a multicellular organism. Thus, the correct answer is 'option A). both produce sex cells.'
Calcium levels in the body are maintained by hormones. If the blood calcium level rises above a set point, calcitonin is secreted by the thyroid gland and sets into motion responses to lower the blood calcium back to the set point. If the blood calcium level falls below a set point, the parathyroid gland secretes parathyroid hormone that sets into motion responses to raise the blood calcium. These homeostatic responses are examples of:
a. positive feedback
b. effectors
c. sensors
d. negative feedback
Answer:
d. negative feedback
Explanation:
Negative feedback responses are the ones that counteract the change. Any alterations in the internal body conditions such as blood calcium levels are sensed by receptors. The information is sent to the brain which in turn commands the effectors such as endocrine glands to secrete the required hormones to restore the normal conditions. Here, changes in the calcium levels are counteracted by the secretion of calcitonin and parathyroid hormones and the calcium is maintained within a narrow range. This represents negative feedback.
EDTA inhibits the activity of DNase during DNA isolation process.
DNase is an enzyme which degrades DNA using divalent metal ions like Mg^{2+} . These metal ions act as cofactor for the proper functioning of DNase.
EDTA chelates the divalent metal ions and thus does not allow DNase to access them.
Therefore in this way DNA is prevented from degradation during its isolation.
Im going to guess either c or d
