At which stage is a human embryo when it attaches to the endometrium in the uterus?
1.blastocyst
2.gastrula
3.hypoblast
4.morula
1
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An invasive species:
A. is any non-native species that has been introduced to an ecosystem. B. is always the competitively dominant species in an ecosystem. C. is any species that has been genetically modified by man. D. is any species that causes disease and death in host organisms. E. is any species that has a negative impact on community diversity.
Regulates movement of mineral ions into root xylem.
Choose the letter of the best match: A. abscisic acid B. trichomes C. aquaporin D. endodermis E. stoma
Most pinnipeds mate:
a. every two years. b. every four years. c. once in their lifetime. d. annually. e. every three years.
In vertebrate nervous systems, information typically flows from sensory neurons to ____ and then to ____
a. the brain; the spinal cord b. a nerve cord; ganglia c. interneurons; sensory neurons d. motor; sensory neurons e. interneurons; motor neurons