The _______ contains the heart, esophagus, trachea, and bronchial tube.

The sharp, inch-long thorns of the crown-of-thorns sea star are its spines. These spines, unlike those of most other sea stars,

vitfil [10]

Answer:

The answer is A) derived from the nematocysts of its prey.

Explanation:

Sea stars mostly eat cnidarians (mollusks) which can contain a large number of nematocysts in their bodies. Therefore it would be possible that this toxin is absorbed from the prey.

5 0

2 years ago

List 3 natural services trees provide ?

fgiga [73]

Trees remove Carbo Dioxide from the atmosphere, they produce oxygen, and they make soil healthier and more arable. I hope this helps! Brainliest would be great. Comment below if it helped.

6 0

2 years ago

Consider the following hypothetical population and compute the statistical measures below: #births = 50,000; #deaths = 10,000; #

777dan777 [17]

Answer:

The birth rate refers to an average number of births in one year per thousand individuals in the population at mid-year.

BR = (total birth in an annum / total population in mid year) * 1000

BR = (50000 / 1000000) * 1000 = 50

Death rate refers to an average number of death in an annum per thousand individuals in a population at mid year. Thus,

DR = (total death / total population in mid year) * 1000

DR = (10000 / 1000000) * 1000 = 10

Annual population growth rate or APGR is calculated as:

APGR = (Birth rate - Death rate) / Death rate

APGR = (50 - 10) / 10 = 4.0 %

Doubling time is the whole sum time needed for a population to get double in size. It is calculated as DT = ln (2) / growth rate

70 / 4.0 = 17.5 years

Thus, population will get double in 17.5 years.

Adjusted (true) growth rate is equal to APGR + (NMR / Death rate)

And NMR = [(immigrants -emigrants) / total population] * 1000

NMR = [(5000 - 20000) / 1000000] * 1000 = -15

Thus, Adjusted (True) growth rate = 4.0 + (-15 /10) = -6%

The adjusted (true) doubling time = ln (2) / Adjusted growth rate

= 70 / -6 = -11.66

This negative sign shows that it will never get double in such situation.

5 0

2 years ago

What is so special about nitrogen in the atmosphere

HACTEHA [7]

Answer:

Firstly, the partial pressure of nitrogen (78%) is crucial to breathing purposes. Without this pressure, the lungs will burst and animals cannot survive.

Secondly, nitrogen is required for the formation of amino acids (building blocks of proteins) and other organic compounds that are necessary for the survival of living organisms. Principally, in the atmosphere, nitrogen is present in the form of molecular nitrogen (N2). N2 is fixed by nitrogen-fixing bacteria that form nitrates and nitrites. These molecules are then used in biochemical processes to produce proteins (amino acids) and other organic compounds. In the absence of nitrogen, these processes could become seize of limited significantly thus affecting life overall.

Thirdly, nitrogen and its derivatives act as greenhouse gases that maintain the Earth's temperature within a range that supports life. Yes, the increased abundance of nitrous oxides is not good because of acid rain and other issues, however, still, the presence of nitrogen is important for life on this planet.

5 0

3 years ago

A researcher had 15 purebred wikl mice which were brown and all females, they were all mated with a male called Bob, All offspri

cestrela7 [59]

Complete question:

A researcher had 15 pure-bred wild mice which were brown and all were females. They were all mated with a male called Bob. All the offspring were brown. These were then crossed among themselves with the following results: 293 brown and 115 white.

(i). Determine the color of Bob.

(ii). Determine which color is dominant.

(iii). Work out the ratio of brown to white in the ‘grandchildren.’

(iv). If the researcher crosses two of the white 'grandchildren', determine the color of their offspring.

Use the Punnett square to work out your answers

Answer:

(i). Determine the color of Bob. BOB IS WHITE

(ii). Determine which color is dominant. BROWN IS DOMINANT

(iii). Work out the ratio of brown to white in the ‘grandchildren.’

PHENOTYPIC RATIO BROWN TO WHITE 3:1

(iv). If the researcher crosses two of the white 'grandchildren', determine the color of their offspring. THE WHOLE PROGENY WILL BE WHITE

Explanation:

Due to technical problems, you will find the complete question, answer, and explanation in the attached files.

Download pdf

4 0

2 years ago